Resume RT-animations after a pauseSurface

Bug: 18203577

The issue occurs as a result of performTraversals() both doing
a window relayout call *and* early-returning because it's not dirty.

To fix this pauseSurface() returns whether or not the RT-side is
"dirty" to force ViewRootImpl to do a draw even if mDirty is
otherwise empty.

Change-Id: I534f367e75d18d273ebf14df3927f5c464ef6bef
diff --git a/libs/hwui/renderthread/CanvasContext.cpp b/libs/hwui/renderthread/CanvasContext.cpp
index aa32541..75bd067 100644
--- a/libs/hwui/renderthread/CanvasContext.cpp
+++ b/libs/hwui/renderthread/CanvasContext.cpp
@@ -123,8 +123,8 @@
     setSurface(window);
 }
 
-void CanvasContext::pauseSurface(ANativeWindow* window) {
-    stopDrawing();
+bool CanvasContext::pauseSurface(ANativeWindow* window) {
+    return mRenderThread.removeFrameCallback(this);
 }
 
 // TODO: don't pass viewport size, it's automatic via EGL
diff --git a/libs/hwui/renderthread/CanvasContext.h b/libs/hwui/renderthread/CanvasContext.h
index 435244e..0cc2c7c 100644
--- a/libs/hwui/renderthread/CanvasContext.h
+++ b/libs/hwui/renderthread/CanvasContext.h
@@ -67,7 +67,7 @@
 
     bool initialize(ANativeWindow* window);
     void updateSurface(ANativeWindow* window);
-    void pauseSurface(ANativeWindow* window);
+    bool pauseSurface(ANativeWindow* window);
     bool hasSurface() { return mNativeWindow.get(); }
 
     void setup(int width, int height, const Vector3& lightCenter, float lightRadius,
diff --git a/libs/hwui/renderthread/RenderProxy.cpp b/libs/hwui/renderthread/RenderProxy.cpp
index 5d55ea6..6d063a4 100644
--- a/libs/hwui/renderthread/RenderProxy.cpp
+++ b/libs/hwui/renderthread/RenderProxy.cpp
@@ -156,15 +156,14 @@
 }
 
 CREATE_BRIDGE2(pauseSurface, CanvasContext* context, ANativeWindow* window) {
-    args->context->pauseSurface(args->window);
-    return NULL;
+    return (void*) args->context->pauseSurface(args->window);
 }
 
-void RenderProxy::pauseSurface(const sp<ANativeWindow>& window) {
+bool RenderProxy::pauseSurface(const sp<ANativeWindow>& window) {
     SETUP_TASK(pauseSurface);
     args->context = mContext;
     args->window = window.get();
-    postAndWait(task);
+    return (bool) postAndWait(task);
 }
 
 CREATE_BRIDGE7(setup, CanvasContext* context, int width, int height,
diff --git a/libs/hwui/renderthread/RenderProxy.h b/libs/hwui/renderthread/RenderProxy.h
index 4989b14..fd1fe05 100644
--- a/libs/hwui/renderthread/RenderProxy.h
+++ b/libs/hwui/renderthread/RenderProxy.h
@@ -69,7 +69,7 @@
 
     ANDROID_API bool initialize(const sp<ANativeWindow>& window);
     ANDROID_API void updateSurface(const sp<ANativeWindow>& window);
-    ANDROID_API void pauseSurface(const sp<ANativeWindow>& window);
+    ANDROID_API bool pauseSurface(const sp<ANativeWindow>& window);
     ANDROID_API void setup(int width, int height, const Vector3& lightCenter, float lightRadius,
             uint8_t ambientShadowAlpha, uint8_t spotShadowAlpha);
     ANDROID_API void setOpaque(bool opaque);
diff --git a/libs/hwui/renderthread/RenderThread.cpp b/libs/hwui/renderthread/RenderThread.cpp
index f887103..38cb4cd 100644
--- a/libs/hwui/renderthread/RenderThread.cpp
+++ b/libs/hwui/renderthread/RenderThread.cpp
@@ -314,9 +314,11 @@
     mPendingRegistrationFrameCallbacks.insert(callback);
 }
 
-void RenderThread::removeFrameCallback(IFrameCallback* callback) {
-    mFrameCallbacks.erase(callback);
-    mPendingRegistrationFrameCallbacks.erase(callback);
+bool RenderThread::removeFrameCallback(IFrameCallback* callback) {
+    size_t erased;
+    erased = mFrameCallbacks.erase(callback);
+    erased |= mPendingRegistrationFrameCallbacks.erase(callback);
+    return erased;
 }
 
 void RenderThread::pushBackFrameCallback(IFrameCallback* callback) {
diff --git a/libs/hwui/renderthread/RenderThread.h b/libs/hwui/renderthread/RenderThread.h
index c461f3a..4126d02 100644
--- a/libs/hwui/renderthread/RenderThread.h
+++ b/libs/hwui/renderthread/RenderThread.h
@@ -80,7 +80,7 @@
 
     // Mimics android.view.Choreographer
     void postFrameCallback(IFrameCallback* callback);
-    void removeFrameCallback(IFrameCallback* callback);
+    bool removeFrameCallback(IFrameCallback* callback);
     // If the callback is currently registered, it will be pushed back until
     // the next vsync. If it is not currently registered this does nothing.
     void pushBackFrameCallback(IFrameCallback* callback);