webview: Initialize synchronous compositor after first activation.

content/browser/android/in_process/synchronous_compositor_impl.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/browser/android/in_process/synchronous_compositor_impl.h"
 
 #include "base/auto_reset.h"
 #include "base/bind.h"
 #include "base/lazy_instance.h"
 #include "base/message_loop/message_loop.h"
@@ skipping 56 matching lines @@
   return FromID(GetInProcessRendererId(), routing_id);
 }
 
 SynchronousCompositorImpl::SynchronousCompositorImpl(WebContents* contents)
     : compositor_client_(NULL),
       output_surface_(NULL),
       begin_frame_source_(nullptr),
       contents_(contents),
       routing_id_(contents->GetRoutingID()),
       input_handler_(NULL),
+      registered_with_client_(false),
       is_active_(false),
       renderer_needs_begin_frames_(false),
       weak_ptr_factory_(this) {
   DCHECK(contents);
   DCHECK_NE(routing_id_, MSG_ROUTING_NONE);
 }
 
 SynchronousCompositorImpl::~SynchronousCompositorImpl() {
   DCHECK(!output_surface_);
   DCHECK(!begin_frame_source_);
@@ skipping 14 matching lines @@
   compositor_client_ = compositor_client;
 
   // SetClient is essentially the constructor and destructor of
   // SynchronousCompositorImpl.
   if (compositor_client_) {
     SynchronousCompositorRegistry::GetInstance()->RegisterCompositor(
         routing_id_, this);
   }
 }
 
+void SynchronousCompositorImpl::RegisterWithClient() {
+  DCHECK(CalledOnValidThread());
+
+  if (registered_with_client_)
+    return;
+
+  SetIsActive(false);
+  compositor_client_->DidInitializeCompositor(this);
+  registered_with_client_ = true;
+}
+
 // static
 void SynchronousCompositor::SetGpuService(
     scoped_refptr<gpu::InProcessCommandBuffer::Service> service) {
   g_factory.Get().SetDeferredGpuService(service);
 }
 
 // static
 void SynchronousCompositor::SetRecordFullDocument(bool record_full_document) {
   g_factory.Get().SetRecordFullDocument(record_full_document);
 }
@@ skipping 12 matching lines @@
   output_surface_ = output_surface;
   begin_frame_source_ = begin_frame_source;
 
   begin_frame_source_->SetCompositor(this);
   output_surface_->SetCompositor(this);
 
   output_surface_->SetTreeActivationCallback(
       base::Bind(&SynchronousCompositorImpl::DidActivatePendingTree,
                  weak_ptr_factory_.GetWeakPtr()));
 
+  SetInputHandler(input_handler);
+
   OnNeedsBeginFramesChange(begin_frame_source_->NeedsBeginFrames());
-
-  compositor_client_->DidInitializeCompositor(this);
-
-  SetInputHandler(input_handler);
+  SetIsActive(true);
 }
 
 void SynchronousCompositorImpl::DidDestroyRendererObjects() {
   DCHECK(output_surface_);
   DCHECK(begin_frame_source_);
   DCHECK(compositor_client_);
 
+  if (registered_with_client_) {
+    compositor_client_->DidDestroyCompositor(this);
+    registered_with_client_ = false;
+  }
+
+  SetIsActive(false);
+  OnNeedsBeginFramesChange(false);
+
+  SetInputHandler(nullptr);
   begin_frame_source_->SetCompositor(nullptr);
   output_surface_->SetCompositor(nullptr);
-  SetInputHandler(nullptr);
-  compositor_client_->DidDestroyCompositor(this);
   output_surface_ = nullptr;
   begin_frame_source_ = nullptr;
 }
 
 scoped_ptr<cc::CompositorFrame> SynchronousCompositorImpl::DemandDrawHw(
     gfx::Size surface_size,
     const gfx::Transform& transform,
     gfx::Rect viewport,
     gfx::Rect clip,
     gfx::Rect viewport_rect_for_tile_priority,
@@ skipping 57 matching lines @@
   if (bytes_limit && !current_bytes_limit) {
     g_factory.Get().CompositorInitializedHardwareDraw();
   } else if (!bytes_limit && current_bytes_limit) {
     g_factory.Get().CompositorReleasedHardwareDraw();
   }
 }
 
 void SynchronousCompositorImpl::PostInvalidate() {
   DCHECK(CalledOnValidThread());
   DCHECK(compositor_client_);
-  compositor_client_->PostInvalidate();
+  if (registered_with_client_)
+    compositor_client_->PostInvalidate();
 }
 
 void SynchronousCompositorImpl::DidChangeRootLayerScrollOffset() {
   if (input_handler_)
     input_handler_->OnRootLayerDelegatedScrollOffsetChanged();
 }
 
 void SynchronousCompositorImpl::SetIsActive(bool is_active) {
   TRACE_EVENT1("cc", "SynchronousCompositorImpl::SetIsActive", "is_active",
                is_active);
@@ skipping 28 matching lines @@
 
   input_handler_ = input_handler;
 
   if (input_handler_)
     input_handler_->SetRootLayerScrollOffsetDelegate(this);
 }
 
 void SynchronousCompositorImpl::DidOverscroll(
     const DidOverscrollParams& params) {
   DCHECK(compositor_client_);
-  compositor_client_->DidOverscroll(params.accumulated_overscroll,
-                                    params.latest_overscroll_delta,
-                                    params.current_fling_velocity);
+  if (registered_with_client_)
+    compositor_client_->DidOverscroll(params.accumulated_overscroll,
+                                      params.latest_overscroll_delta,
+                                      params.current_fling_velocity);
 }
 
 void SynchronousCompositorImpl::DidStopFlinging() {
   // It's important that the fling-end notification follow the same path as it
   // takes on other platforms (using an IPC). This ensures consistent
   // bookkeeping at all stages of the input pipeline.
   contents_->GetRenderProcessHost()->OnMessageReceived(
       InputHostMsg_DidStopFlinging(routing_id_));
 }
 
@@ skipping 10 matching lines @@
   RenderProcessHost* rph = contents_->GetRenderProcessHost();
   for (ScopedVector<IPC::Message>::const_iterator i = messages.begin();
        i != messages.end();
        ++i) {
     rph->OnMessageReceived(**i);
   }
 }
 
 void SynchronousCompositorImpl::DidActivatePendingTree() {
   DCHECK(compositor_client_);
+  if (!registered_with_client_)
+    RegisterWithClient();
+  DCHECK(registered_with_client_);
   compositor_client_->DidUpdateContent();
   DeliverMessages();
 }
 
 gfx::ScrollOffset SynchronousCompositorImpl::GetTotalScrollOffset() {
   DCHECK(CalledOnValidThread());
   DCHECK(compositor_client_);
+  if (!registered_with_client_)
+    return gfx::ScrollOffset();
   // TODO(miletus): Make GetTotalRootLayerScrollOffset return
   // ScrollOffset. crbug.com/414283.
   return gfx::ScrollOffset(
       compositor_client_->GetTotalRootLayerScrollOffset());
 }
 
 bool SynchronousCompositorImpl::IsExternalFlingActive() const {
   DCHECK(CalledOnValidThread());
   DCHECK(compositor_client_);
+  if (!registered_with_client_)
+    return false;
   return compositor_client_->IsExternalFlingActive();
 }
 
 void SynchronousCompositorImpl::UpdateRootLayerState(
     const gfx::ScrollOffset& total_scroll_offset,
     const gfx::ScrollOffset& max_scroll_offset,
     const gfx::SizeF& scrollable_size,
     float page_scale_factor,
     float min_page_scale_factor,
     float max_page_scale_factor) {
   DCHECK(CalledOnValidThread());
   DCHECK(compositor_client_);
 
-  // TODO(miletus): Pass in ScrollOffset. crbug.com/414283.
-  compositor_client_->UpdateRootLayerState(
-      gfx::ScrollOffsetToVector2dF(total_scroll_offset),
-      gfx::ScrollOffsetToVector2dF(max_scroll_offset),
-      scrollable_size,
-      page_scale_factor,
-      min_page_scale_factor,
-      max_page_scale_factor);
+  if (registered_with_client_)

[boliu, 2015/05/30 01:06:29]

style: Need braces for if statements with multi-line body

+    // TODO(miletus): Pass in ScrollOffset. crbug.com/414283.
+    compositor_client_->UpdateRootLayerState(
+        gfx::ScrollOffsetToVector2dF(total_scroll_offset),
+        gfx::ScrollOffsetToVector2dF(max_scroll_offset),
+        scrollable_size,
+        page_scale_factor,
+        min_page_scale_factor,
+        max_page_scale_factor);
 }
 
 // Not using base::NonThreadSafe as we want to enforce a more exacting threading
 // requirement: SynchronousCompositorImpl() must only be used on the UI thread.
 bool SynchronousCompositorImpl::CalledOnValidThread() const {
   return BrowserThread::CurrentlyOn(BrowserThread::UI);
 }
 
 // static
 void SynchronousCompositor::SetClientForWebContents(
     WebContents* contents,
     SynchronousCompositorClient* client) {
   DCHECK(contents);
   if (client) {
     g_factory.Get();  // Ensure it's initialized.
     SynchronousCompositorImpl::CreateForWebContents(contents);
   }
   SynchronousCompositorImpl* instance =
       SynchronousCompositorImpl::FromWebContents(contents);
   DCHECK(instance);
   instance->SetClient(client);
 }
 
 }  // namespace content