cc: Unify context losing machinery

cc/single_thread_proxy.cc

Index: cc/single_thread_proxy.cc
diff --git a/cc/single_thread_proxy.cc b/cc/single_thread_proxy.cc
index 63d70d8f87dba5aae375db422e2e00e8d0c97c5c..27dcb4240ccc1a8ebe8898f3fe8dc87999afca0d 100644
--- a/cc/single_thread_proxy.cc
+++ b/cc/single_thread_proxy.cc
@@ -51,12 +51,15 @@ bool SingleThreadProxy::compositeAndReadback(void *pixels, const gfx::Rect& rect
     if (!commitAndComposite())
         return false;
 
-    m_layerTreeHostImpl->readback(pixels, rect);
+    {
+        DebugScopedSetImplThread impl(this);
+        m_layerTreeHostImpl->readback(pixels, rect);
 
-    if (m_layerTreeHostImpl->isContextLost())
-        return false;
+        if (m_layerTreeHostImpl->isContextLost())
+            return false;
 
-    m_layerTreeHostImpl->swapBuffers();
+        m_layerTreeHostImpl->swapBuffers();
+    }
     didSwapFrame();
 
     return true;
@@ -164,8 +167,9 @@ const RendererCapabilities& SingleThreadProxy::rendererCapabilities() const
 void SingleThreadProxy::loseOutputSurface()
 {
     DCHECK(Proxy::isMainThread());
-    m_layerTreeHost->didLoseOutputSurface();
-    m_outputSurfaceLost = true;
+
+    DebugScopedSetImplThread impl(this);
+    m_layerTreeHostImpl->resourceProvider()->loseOutputSurface();
 }
 
 void SingleThreadProxy::setNeedsAnimate()
@@ -310,6 +314,12 @@ void SingleThreadProxy::sendManagedMemoryStats()
         m_layerTreeHost->contentsTextureManager()->memoryUseBytes());
 }
 
+void SingleThreadProxy::didLoseOutputSurfaceOnImplThread()
+{
+    // Cause a commit so we can notice the lost context.
+    setNeedsCommitOnImplThread();
+}
+
 // Called by the legacy scheduling path (e.g. where render_widget does the scheduling)
 void SingleThreadProxy::compositeImmediately()
 {
@@ -379,10 +389,10 @@ bool SingleThreadProxy::doComposite()
         m_layerTreeHostImpl->prepareToDraw(frame);
         m_layerTreeHostImpl->drawLayers(frame);
         m_layerTreeHostImpl->didDrawAllLayers(frame);
+        m_outputSurfaceLost = m_layerTreeHostImpl->isContextLost();
     }
 
-    if (m_layerTreeHostImpl->isContextLost()) {
-        m_outputSurfaceLost = true;
+    if (m_outputSurfaceLost) {
         m_layerTreeHost->didLoseOutputSurface();
         return false;
     }