webview: Initialize synchronous compositor after first activation.

content/browser/android/in_process/synchronous_compositor_impl.cc

Index: content/browser/android/in_process/synchronous_compositor_impl.cc
diff --git a/content/browser/android/in_process/synchronous_compositor_impl.cc b/content/browser/android/in_process/synchronous_compositor_impl.cc
index d3c6b830b7082bf6e2dec32f803b6751d249aa47..7940597124474939cf5bb6f869a21cb5c51e57e4 100644
--- a/content/browser/android/in_process/synchronous_compositor_impl.cc
+++ b/content/browser/android/in_process/synchronous_compositor_impl.cc
@@ -74,6 +74,7 @@ SynchronousCompositorImpl::SynchronousCompositorImpl(WebContents* contents)
       contents_(contents),
       routing_id_(contents->GetRoutingID()),
       input_handler_(NULL),
+      has_initialized_(false),
       is_active_(false),
       renderer_needs_begin_frames_(false),
       weak_ptr_factory_(this) {
@@ -140,11 +141,9 @@ void SynchronousCompositorImpl::DidInitializeRendererObjects(
       base::Bind(&SynchronousCompositorImpl::DidActivatePendingTree,
                  weak_ptr_factory_.GetWeakPtr()));
 
-  OnNeedsBeginFramesChange(begin_frame_source_->NeedsBeginFrames());
-
-  compositor_client_->DidInitializeCompositor(this);
-
   SetInputHandler(input_handler);
+
+  OnNeedsBeginFramesChange(begin_frame_source_->NeedsBeginFrames());
 }
 
 void SynchronousCompositorImpl::DidDestroyRendererObjects() {
@@ -152,6 +151,8 @@ void SynchronousCompositorImpl::DidDestroyRendererObjects() {
   DCHECK(begin_frame_source_);
   DCHECK(compositor_client_);
 
+  OnNeedsBeginFramesChange(false);
+
   begin_frame_source_->SetCompositor(nullptr);
   output_surface_->SetCompositor(nullptr);
   SetInputHandler(nullptr);
@@ -263,7 +264,8 @@ void SynchronousCompositorImpl::UpdateNeedsBeginFrames() {
   RenderWidgetHostViewAndroid* rwhv = static_cast<RenderWidgetHostViewAndroid*>(
       contents_->GetRenderWidgetHostView());
   if (rwhv)
-    rwhv->OnSetNeedsBeginFrames(is_active_ && renderer_needs_begin_frames_);
+    rwhv->OnSetNeedsBeginFrames((is_active_ || !has_initialized_) &&
+                                renderer_needs_begin_frames_);
 }
 
 void SynchronousCompositorImpl::SetInputHandler(
@@ -315,6 +317,10 @@ void SynchronousCompositorImpl::DeliverMessages() {
 
 void SynchronousCompositorImpl::DidActivatePendingTree() {
   DCHECK(compositor_client_);
+  if (!has_initialized_) {
+    has_initialized_ = true;
+    compositor_client_->DidInitializeCompositor(this);
+  }
   compositor_client_->DidUpdateContent();
   DeliverMessages();
 }