SurfaceFlinger: Add parent-less relative layering.

This is a temporary functionality for the intermediate state where not
all child-surface like things in WM land are ported to use Child
Surfaces. In particular, we have ported SurfaceView to use child
surfaces and relative Z ordering. However the TV frameworks provide a
View framework component which overlays views over the SurfaceView but
below the main application window. Since we have not ported View
framework surfaces to use child layers, there is nothing the WM or
View Framework can do about this situation. Luckily the WM API's to
have requested this are @hide but we have the one media framework
component using it. In order to solve this issue we provide a method
to set Z ordering relative to another window without inheriting
its coordinate space as a child window would. This way the WM can
recognize these TYPE_APPLICATION_MEDIA_OVERLAY windows and Z-order
them at -1 with respect to the parents (and the SurfaceView can be at
-2).

Test: Included in transaction tests. Also manual test of bug repro steps with accomp frameworks/base CL
Bug: 36693738
Change-Id: I921852d3d34f67f79ec745b9703f9e679867e7a1

1 files changed, 21 insertions, 0 deletions

diff --git a/libs/gui/SurfaceComposerClient.cpp b/libs/gui/SurfaceComposerClient.cpp
index 56c7586041..8c8384399c 100644
--- a/libs/gui/SurfaceComposerClient.cpp
+++ b/libs/gui/SurfaceComposerClient.cpp
@@ -149,6 +149,8 @@ public:
             uint32_t w, uint32_t h);
     status_t setLayer(const sp<SurfaceComposerClient>& client, const sp<IBinder>& id,
             int32_t z);
+    status_t setRelativeLayer(const sp<SurfaceComposerClient>& client, const sp<IBinder>& id,
+            const sp<IBinder>& relativeTo, int32_t z);
     status_t setFlags(const sp<SurfaceComposerClient>& client, const sp<IBinder>& id,
             uint32_t flags, uint32_t mask);
     status_t setTransparentRegionHint(
@@ -343,6 +345,20 @@ status_t Composer::setLayer(const sp<SurfaceComposerClient>& client,
     return NO_ERROR;
 }
 
+status_t Composer::setRelativeLayer(const sp<SurfaceComposerClient>& client,
+        const sp<IBinder>& id, const sp<IBinder>& relativeTo,
+        int32_t z) {
+    Mutex::Autolock _l(mLock);
+    layer_state_t* s = getLayerStateLocked(client, id);
+    if (!s) {
+        return BAD_INDEX;
+    }
+    s->what |= layer_state_t::eRelativeLayerChanged;
+    s->relativeLayerHandle = relativeTo;
+    s->z = z;
+    return NO_ERROR;
+}
+
 status_t Composer::setFlags(const sp<SurfaceComposerClient>& client,
         const sp<IBinder>& id, uint32_t flags,
         uint32_t mask) {
@@ -760,6 +776,11 @@ status_t SurfaceComposerClient::setLayer(const sp<IBinder>& id, int32_t z) {
     return getComposer().setLayer(this, id, z);
 }
 
+status_t SurfaceComposerClient::setRelativeLayer(const sp<IBinder>& id,
+        const sp<IBinder>& relativeTo, int32_t z) {
+    return getComposer().setRelativeLayer(this, id, relativeTo, z);
+}
+
 status_t SurfaceComposerClient::hide(const sp<IBinder>& id) {
     return getComposer().setFlags(this, id,
             layer_state_t::eLayerHidden,