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 33 matching lines @@
 base::LazyInstance<SynchronousCompositorFactoryImpl>::Leaky g_factory =
     LAZY_INSTANCE_INITIALIZER;
 
 }  // namespace
 
 DEFINE_WEB_CONTENTS_USER_DATA_KEY(SynchronousCompositorImpl);
 
 // static
 SynchronousCompositorImpl* SynchronousCompositorImpl::FromID(int process_id,
                                                              int routing_id) {
-  if (g_factory == NULL)
-    return NULL;
+  if (g_factory == nullptr)
+    return nullptr;
   RenderViewHost* rvh = RenderViewHost::FromID(process_id, routing_id);
   if (!rvh)
-    return NULL;
+    return nullptr;
   WebContents* contents = WebContents::FromRenderViewHost(rvh);
   if (!contents)
-    return NULL;
+    return nullptr;
   return FromWebContents(contents);
 }
 
 SynchronousCompositorImpl* SynchronousCompositorImpl::FromRoutingID(
     int routing_id) {
   return FromID(GetInProcessRendererId(), routing_id);
 }
 
 SynchronousCompositorImpl::SynchronousCompositorImpl(WebContents* contents)
-    : compositor_client_(NULL),
-      output_surface_(NULL),
+    : compositor_client_(nullptr),
+      output_surface_(nullptr),
       begin_frame_source_(nullptr),
       contents_(contents),
       routing_id_(contents->GetRoutingID()),
-      input_handler_(NULL),
-      is_active_(false),
+      input_handler_(nullptr),
+      registered_with_client_(false),
+      is_active_(true),
       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_);
   DCHECK(!input_handler_);
@@ skipping 13 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());
+  DCHECK(compositor_client_);
+  DCHECK(output_surface_);
+  DCHECK(input_handler_);
+  DCHECK(!registered_with_client_);
+  registered_with_client_ = true;
+
+  compositor_client_->DidInitializeCompositor(this);
+
+  output_surface_->SetTreeActivationCallback(
+    base::Bind(&SynchronousCompositorImpl::DidActivatePendingTree,
+               weak_ptr_factory_.GetWeakPtr()));
+
+  // Setting the delegate causes UpdateRootLayerState immediately so do it
+  // after setting the client.
+  input_handler_->SetRootLayerScrollOffsetDelegate(this);
+}
+
 // 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);
 }
 
 void SynchronousCompositorImpl::DidInitializeRendererObjects(
     SynchronousCompositorOutputSurface* output_surface,
     SynchronousCompositorExternalBeginFrameSource* begin_frame_source,
     cc::InputHandler* input_handler) {
   DCHECK(!output_surface_);
   DCHECK(!begin_frame_source_);
   DCHECK(output_surface);
   DCHECK(begin_frame_source);
   DCHECK(compositor_client_);
   DCHECK(input_handler);
 
   output_surface_ = output_surface;
   begin_frame_source_ = begin_frame_source;
+  input_handler_ = input_handler;
 
+  output_surface_->SetCompositor(this);
   begin_frame_source_->SetCompositor(this);
-  output_surface_->SetCompositor(this);
-
-  output_surface_->SetTreeActivationCallback(
-      base::Bind(&SynchronousCompositorImpl::DidActivatePendingTree,
-                 weak_ptr_factory_.GetWeakPtr()));
-
-  OnNeedsBeginFramesChange(begin_frame_source_->NeedsBeginFrames());
-
-  compositor_client_->DidInitializeCompositor(this);
-
-  SetInputHandler(input_handler);
 }
 
 void SynchronousCompositorImpl::DidDestroyRendererObjects() {
   DCHECK(output_surface_);
   DCHECK(begin_frame_source_);
   DCHECK(compositor_client_);
 
+  if (registered_with_client_) {
+    input_handler_->SetRootLayerScrollOffsetDelegate(nullptr);
+    output_surface_->SetTreeActivationCallback(base::Closure());
+    compositor_client_->DidDestroyCompositor(this);
+    registered_with_client_ = false;
+  }
+
   begin_frame_source_->SetCompositor(nullptr);
   output_surface_->SetCompositor(nullptr);
-  SetInputHandler(nullptr);
-  compositor_client_->DidDestroyCompositor(this);
+
+  input_handler_ = nullptr;
+  begin_frame_source_ = nullptr;
   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,
     const gfx::Transform& transform_for_tile_priority) {
   DCHECK(CalledOnValidThread());
@@ skipping 55 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);
   is_active_ = is_active;
   UpdateNeedsBeginFrames();
 }
 
 void SynchronousCompositorImpl::OnNeedsBeginFramesChange(
     bool needs_begin_frames) {
   renderer_needs_begin_frames_ = needs_begin_frames;
   UpdateNeedsBeginFrames();
 }
 
 void SynchronousCompositorImpl::BeginFrame(const cc::BeginFrameArgs& args) {
+  if (!registered_with_client_) {
+    RegisterWithClient();
+    DCHECK(registered_with_client_);
+  }
   if (begin_frame_source_)
     begin_frame_source_->BeginFrame(args);
 }
 
 void SynchronousCompositorImpl::UpdateNeedsBeginFrames() {
   RenderWidgetHostViewAndroid* rwhv = static_cast<RenderWidgetHostViewAndroid*>(
       contents_->GetRenderWidgetHostView());
   if (rwhv)
     rwhv->OnSetNeedsBeginFrames(is_active_ && renderer_needs_begin_frames_);
 }
 
-void SynchronousCompositorImpl::SetInputHandler(
-    cc::InputHandler* input_handler) {
-  DCHECK(CalledOnValidThread());
-
-  if (input_handler_)
-    input_handler_->SetRootLayerScrollOffsetDelegate(NULL);
-
-  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_);
-  compositor_client_->DidUpdateContent();
+  if (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_) {
+    // 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