WebView: Add the definition of the renderer importance API.

The renderer importance API is used to specify how important
out-of-process WebView renderer services are for the purposes of OOM
killing and scheduling with respect to the binding application.

This allows an application to - for example - specify that renderers can
be killed while the application is not in the foreground, thus cleaning
up additional resources.

Bug: 30824898
Test: Tests await Chromium change.
Change-Id: I6dca3d427d6cdb5cb7e0be6f7fb8ece64bd24af9

6 files changed, 132 insertions, 0 deletions

diff --git a/api/current.txt b/api/current.txt
index 725f1f057c76..21f547912bc1 100644
--- a/api/current.txt
+++ b/api/current.txt
@@ -46575,6 +46575,7 @@ package android.webkit {
   public abstract class RenderProcessGoneDetail {
     ctor public RenderProcessGoneDetail();
     method public abstract boolean didCrash();
+    method public abstract int rendererPriorityAtExit();
   }
 
   public class ServiceWorkerClient {
@@ -46991,6 +46992,8 @@ package android.webkit {
     method public deprecated java.lang.String[] getHttpAuthUsernamePassword(java.lang.String, java.lang.String);
     method public java.lang.String getOriginalUrl();
     method public int getProgress();
+    method public boolean getRendererPriorityWaivedWhenNotVisible();
+    method public int getRendererRequestedPriority();
     method public deprecated float getScale();
     method public android.webkit.WebSettings getSettings();
     method public java.lang.String getTitle();
@@ -47038,6 +47041,7 @@ package android.webkit {
     method public deprecated void setMapTrackballToArrowKeys(boolean);
     method public void setNetworkAvailable(boolean);
     method public deprecated void setPictureListener(android.webkit.WebView.PictureListener);
+    method public void setRendererPriorityPolicy(int, boolean);
     method public deprecated void setVerticalScrollbarOverlay(boolean);
     method public void setWebChromeClient(android.webkit.WebChromeClient);
     method public static void setWebContentsDebuggingEnabled(boolean);
@@ -47047,6 +47051,9 @@ package android.webkit {
     method public void zoomBy(float);
     method public boolean zoomIn();
     method public boolean zoomOut();
+    field public static final int RENDERER_PRIORITY_BOUND = 1; // 0x1
+    field public static final int RENDERER_PRIORITY_IMPORTANT = 2; // 0x2
+    field public static final int RENDERER_PRIORITY_WAIVED = 0; // 0x0
     field public static final java.lang.String SCHEME_GEO = "geo:0,0?q=";
     field public static final java.lang.String SCHEME_MAILTO = "mailto:";
     field public static final java.lang.String SCHEME_TEL = "tel:";
diff --git a/api/system-current.txt b/api/system-current.txt
index 0b5040a847d1..afc3d0928592 100644
--- a/api/system-current.txt
+++ b/api/system-current.txt
@@ -49907,6 +49907,7 @@ package android.webkit {
   public abstract class RenderProcessGoneDetail {
     ctor public RenderProcessGoneDetail();
     method public abstract boolean didCrash();
+    method public abstract int rendererPriorityAtExit();
   }
 
   public class ServiceWorkerClient {
@@ -50362,6 +50363,8 @@ package android.webkit {
     method public deprecated java.lang.String[] getHttpAuthUsernamePassword(java.lang.String, java.lang.String);
     method public java.lang.String getOriginalUrl();
     method public int getProgress();
+    method public boolean getRendererPriorityWaivedWhenNotVisible();
+    method public int getRendererRequestedPriority();
     method public deprecated float getScale();
     method public android.webkit.WebSettings getSettings();
     method public java.lang.String getTitle();
@@ -50410,6 +50413,7 @@ package android.webkit {
     method public deprecated void setMapTrackballToArrowKeys(boolean);
     method public void setNetworkAvailable(boolean);
     method public deprecated void setPictureListener(android.webkit.WebView.PictureListener);
+    method public void setRendererPriorityPolicy(int, boolean);
     method public deprecated void setVerticalScrollbarOverlay(boolean);
     method public void setWebChromeClient(android.webkit.WebChromeClient);
     method public static void setWebContentsDebuggingEnabled(boolean);
@@ -50420,6 +50424,9 @@ package android.webkit {
     method public boolean zoomIn();
     method public boolean zoomOut();
     field public static final java.lang.String DATA_REDUCTION_PROXY_SETTING_CHANGED = "android.webkit.DATA_REDUCTION_PROXY_SETTING_CHANGED";
+    field public static final int RENDERER_PRIORITY_BOUND = 1; // 0x1
+    field public static final int RENDERER_PRIORITY_IMPORTANT = 2; // 0x2
+    field public static final int RENDERER_PRIORITY_WAIVED = 0; // 0x0
     field public static final java.lang.String SCHEME_GEO = "geo:0,0?q=";
     field public static final java.lang.String SCHEME_MAILTO = "mailto:";
     field public static final java.lang.String SCHEME_TEL = "tel:";
@@ -50641,6 +50648,8 @@ package android.webkit {
     method public abstract java.lang.String[] getHttpAuthUsernamePassword(java.lang.String, java.lang.String);
     method public abstract java.lang.String getOriginalUrl();
     method public abstract int getProgress();
+    method public abstract boolean getRendererPriorityWaivedWhenNotVisible();
+    method public abstract int getRendererRequestedPriority();
     method public abstract float getScale();
     method public abstract android.webkit.WebViewProvider.ScrollDelegate getScrollDelegate();
     method public abstract android.webkit.WebSettings getSettings();
@@ -50695,6 +50704,7 @@ package android.webkit {
     method public abstract void setMapTrackballToArrowKeys(boolean);
     method public abstract void setNetworkAvailable(boolean);
     method public abstract void setPictureListener(android.webkit.WebView.PictureListener);
+    method public abstract void setRendererPriorityPolicy(int, boolean);
     method public abstract void setVerticalScrollbarOverlay(boolean);
     method public abstract void setWebChromeClient(android.webkit.WebChromeClient);
     method public abstract void setWebViewClient(android.webkit.WebViewClient);
diff --git a/api/test-current.txt b/api/test-current.txt
index f5212327900a..621045a89baf 100644
--- a/api/test-current.txt
+++ b/api/test-current.txt
@@ -46873,6 +46873,7 @@ package android.webkit {
   public abstract class RenderProcessGoneDetail {
     ctor public RenderProcessGoneDetail();
     method public abstract boolean didCrash();
+    method public abstract int rendererPriorityAtExit();
   }
 
   public class ServiceWorkerClient {
@@ -47289,6 +47290,8 @@ package android.webkit {
     method public deprecated java.lang.String[] getHttpAuthUsernamePassword(java.lang.String, java.lang.String);
     method public java.lang.String getOriginalUrl();
     method public int getProgress();
+    method public boolean getRendererPriorityWaivedWhenNotVisible();
+    method public int getRendererRequestedPriority();
     method public deprecated float getScale();
     method public android.webkit.WebSettings getSettings();
     method public java.lang.String getTitle();
@@ -47336,6 +47339,7 @@ package android.webkit {
     method public deprecated void setMapTrackballToArrowKeys(boolean);
     method public void setNetworkAvailable(boolean);
     method public deprecated void setPictureListener(android.webkit.WebView.PictureListener);
+    method public void setRendererPriorityPolicy(int, boolean);
     method public deprecated void setVerticalScrollbarOverlay(boolean);
     method public void setWebChromeClient(android.webkit.WebChromeClient);
     method public static void setWebContentsDebuggingEnabled(boolean);
@@ -47345,6 +47349,9 @@ package android.webkit {
     method public void zoomBy(float);
     method public boolean zoomIn();
     method public boolean zoomOut();
+    field public static final int RENDERER_PRIORITY_BOUND = 1; // 0x1
+    field public static final int RENDERER_PRIORITY_IMPORTANT = 2; // 0x2
+    field public static final int RENDERER_PRIORITY_WAIVED = 0; // 0x0
     field public static final java.lang.String SCHEME_GEO = "geo:0,0?q=";
     field public static final java.lang.String SCHEME_MAILTO = "mailto:";
     field public static final java.lang.String SCHEME_TEL = "tel:";
diff --git a/core/java/android/webkit/RenderProcessGoneDetail.java b/core/java/android/webkit/RenderProcessGoneDetail.java
index 77d85963ce2d..1c793993909d 100644
--- a/core/java/android/webkit/RenderProcessGoneDetail.java
+++ b/core/java/android/webkit/RenderProcessGoneDetail.java
@@ -32,4 +32,15 @@ public abstract class RenderProcessGoneDetail {
      *         system.
      **/
     public abstract boolean didCrash();
+
+    /**
+     * Returns the renderer priority that was set at the time that the
+     * renderer exited.  This may be greater than the priority that
+     * any individual {@link WebView} requested using
+     * {@link WebView#setRendererPriorityPolicy}.
+     *
+     * @return the priority of the renderer at exit.
+     **/
+    @WebView.RendererPriority
+    public abstract int rendererPriorityAtExit();
 }
diff --git a/core/java/android/webkit/WebView.java b/core/java/android/webkit/WebView.java
index f98c099f053f..1e7cddfcda92 100644
--- a/core/java/android/webkit/WebView.java
+++ b/core/java/android/webkit/WebView.java
@@ -16,6 +16,7 @@
 
 package android.webkit;
 
+import android.annotation.IntDef;
 import android.annotation.NonNull;
 import android.annotation.SystemApi;
 import android.annotation.Widget;
@@ -60,6 +61,8 @@ import android.widget.AbsoluteLayout;
 
 import java.io.BufferedWriter;
 import java.io.File;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
 import java.util.Map;
 
 /**
@@ -2151,6 +2154,94 @@ public class WebView extends AbsoluteLayout
         return mProvider.findHierarchyView(className, hashCode);
     }
 
+    /** @hide */
+    @IntDef({
+        RENDERER_PRIORITY_WAIVED,
+        RENDERER_PRIORITY_BOUND,
+        RENDERER_PRIORITY_IMPORTANT
+    })
+    @Retention(RetentionPolicy.SOURCE)
+    public @interface RendererPriority {}
+
+    /**
+     * The renderer associated with this WebView is bound with
+     * {@link Context#BIND_WAIVE_PRIORITY}. At this priority level
+     * {@link WebView} renderers will be strong targets for out of memory
+     * killing.
+     *
+     * Use with {@link #setRendererPriorityPolicy}.
+     */
+    public static final int RENDERER_PRIORITY_WAIVED = 0;
+    /**
+     * The renderer associated with this WebView is bound with
+     * the default priority for services.
+     *
+     * Use with {@link #setRendererPriorityPolicy}.
+     */
+    public static final int RENDERER_PRIORITY_BOUND = 1;
+    /**
+     * The renderer associated with this WebView is bound with
+     * {@link Context#BIND_IMPORTANT}.
+     *
+     * Use with {@link #setRendererPriorityPolicy}.
+     */
+    public static final int RENDERER_PRIORITY_IMPORTANT = 2;
+
+    /**
+     * Set the renderer priority policy for this {@link WebView}. The
+     * priority policy will be used to determine whether an out of
+     * process renderer should be considered to be a target for OOM
+     * killing.
+     *
+     * Because a renderer can be associated with more than one
+     * WebView, the final priority it is computed as the maximum of
+     * any attached WebViews. When a WebView is destroyed it will
+     * cease to be considerered when calculating the renderer
+     * priority. Once no WebViews remain associated with the renderer,
+     * the priority of the renderer will be reduced to
+     * {@link #RENDERER_PRIORITY_WAIVED}.
+     *
+     * The default policy is to set the priority to
+     * {@link #RENDERER_PRIORITY_IMPORTANT} regardless of visibility,
+     * and this should not be changed unless the caller also handles
+     * renderer crashes with
+     * {@link WebViewClient#onRenderProcessGone}. Any other setting
+     * will result in WebView renderers being killed by the system
+     * more aggressively than the application.
+     *
+     * @param rendererRequestedPriority the minimum priority at which
+     *        this WebView desires the renderer process to be bound.
+     * @param waivedWhenNotVisible if true, this flag specifies that
+     *        when this WebView is not visible, it will be treated as
+     *        if it had requested a priority of
+     *        {@link #RENDERER_PRIORITY_WAIVED}.
+     */
+    public void setRendererPriorityPolicy(
+            @RendererPriority int rendererRequestedPriority,
+            boolean waivedWhenNotVisible) {
+        mProvider.setRendererPriorityPolicy(rendererRequestedPriority, waivedWhenNotVisible);
+    }
+
+    /**
+     * Get the requested renderer priority for this WebView.
+     *
+     * @return the requested renderer priority policy.
+     */
+    @RendererPriority
+    public int getRendererRequestedPriority() {
+        return mProvider.getRendererRequestedPriority();
+    }
+
+    /**
+     * Return whether this WebView requests a priority of
+     * {@link #RENDERER_PRIORITY_WAIVED} when not visible.
+     *
+     * @return whether this WebView requests a priority of
+     * {@link #RENDERER_PRIORITY_WAIVED} when not visible.
+     */
+    public boolean getRendererPriorityWaivedWhenNotVisible() {
+        return mProvider.getRendererPriorityWaivedWhenNotVisible();
+    }
     //-------------------------------------------------------------------------
     // Interface for WebView providers
     //-------------------------------------------------------------------------
diff --git a/core/java/android/webkit/WebViewProvider.java b/core/java/android/webkit/WebViewProvider.java
index dd1b0d2d17a4..ffc18b1e9c36 100644
--- a/core/java/android/webkit/WebViewProvider.java
+++ b/core/java/android/webkit/WebViewProvider.java
@@ -269,6 +269,12 @@ public interface WebViewProvider {
 
     public View findHierarchyView(String className, int hashCode);
 
+    public void setRendererPriorityPolicy(int rendererRequestedPriority, boolean waivedWhenNotVisible);
+
+    public int getRendererRequestedPriority();
+
+    public boolean getRendererPriorityWaivedWhenNotVisible();
+
     //-------------------------------------------------------------------------
     // Provider internal methods
     //-------------------------------------------------------------------------