Remove LayerScrollOffsetDelegate, make all input paths go thru proxy.

This removes the cc::LayerScrollOffsetDelegate interface, moving it
into the InputHandlerClient interface.

It also removes the pointer to cc::LayerTreeHostImpl (as a
cc::InputHandler*) from the WebView embedder code. Instead make the
WebView code always go through the SynchronousInputHandlerProxy (which
is the InputHandlerProxy) to talk to the compositor about input-related
things.

R=boliu, jdduke@chromium.org
BUG=531746
CQ_INCLUDE_TRYBOTS=tryserver.blink:linux_blink_rel

Review URL: https://codereview.chromium.org/1353013002

Cr-Commit-Position: refs/heads/master@{#350056}

6 files changed, 21 insertions, 37 deletions

diff --git a/content/browser/android/in_process/synchronous_compositor_impl.cc b/content/browser/android/in_process/synchronous_compositor_impl.cc
index 06d622c..9846672 100644
--- a/content/browser/android/in_process/synchronous_compositor_impl.cc
+++ b/content/browser/android/in_process/synchronous_compositor_impl.cc
@@ -8,7 +8,6 @@
 #include "base/bind.h"
 #include "base/lazy_instance.h"
 #include "base/message_loop/message_loop.h"
-#include "cc/input/input_handler.h"
 #include "content/browser/android/in_process/synchronous_compositor_external_begin_frame_source.h"
 #include "content/browser/android/in_process/synchronous_compositor_factory_impl.h"
 #include "content/browser/android/in_process/synchronous_compositor_registry.h"
@@ -21,6 +20,7 @@
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/render_process_host.h"
 #include "content/public/browser/render_view_host.h"
+#include "ui/gfx/geometry/scroll_offset.h"
 #include "ui/gl/gl_surface.h"
 
 namespace content {
@@ -79,7 +79,7 @@ SynchronousCompositorImpl::SynchronousCompositorImpl(WebContents* contents)
       begin_frame_source_(nullptr),
       contents_(contents),
       routing_id_(contents->GetRoutingID()),
-      input_handler_(nullptr),
+      synchronous_input_handler_proxy_(nullptr),
       registered_with_client_(false),
       is_active_(true),
       renderer_needs_begin_frames_(false),
@@ -92,7 +92,7 @@ SynchronousCompositorImpl::SynchronousCompositorImpl(WebContents* contents)
 SynchronousCompositorImpl::~SynchronousCompositorImpl() {
   DCHECK(!output_surface_);
   DCHECK(!begin_frame_source_);
-  DCHECK(!input_handler_);
+  DCHECK(!synchronous_input_handler_proxy_);
 }
 
 void SynchronousCompositorImpl::SetClient(
@@ -120,7 +120,7 @@ void SynchronousCompositorImpl::RegisterWithClient() {
   DCHECK(CalledOnValidThread());
   DCHECK(compositor_client_);
   DCHECK(output_surface_);
-  DCHECK(input_handler_);
+  DCHECK(synchronous_input_handler_proxy_);
   DCHECK(!registered_with_client_);
   registered_with_client_ = true;
 
@@ -130,12 +130,10 @@ void SynchronousCompositorImpl::RegisterWithClient() {
     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);
   // This disables the input system from animating inputs autonomously, instead
   // routing all input animations through the SynchronousInputHandler, which is
-  // |this| class.
+  // |this| class. Calling this causes an UpdateRootLayerState() immediately so,
+  // do it after setting the client.
   synchronous_input_handler_proxy_->SetOnlySynchronouslyAnimateRootFlings(this);
 }
 
@@ -155,19 +153,16 @@ void SynchronousCompositor::SetUseIpcCommandBuffer() {
 void SynchronousCompositorImpl::DidInitializeRendererObjects(
     SynchronousCompositorOutputSurface* output_surface,
     SynchronousCompositorExternalBeginFrameSource* begin_frame_source,
-    cc::InputHandler* input_handler,
     SynchronousInputHandlerProxy* synchronous_input_handler_proxy) {
   DCHECK(!output_surface_);
   DCHECK(!begin_frame_source_);
   DCHECK(output_surface);
   DCHECK(begin_frame_source);
   DCHECK(compositor_client_);
-  DCHECK(input_handler);
   DCHECK(synchronous_input_handler_proxy);
 
   output_surface_ = output_surface;
   begin_frame_source_ = begin_frame_source;
-  input_handler_ = input_handler;
   synchronous_input_handler_proxy_ = synchronous_input_handler_proxy;
 
   output_surface_->SetCompositor(this);
@@ -180,16 +175,18 @@ void SynchronousCompositorImpl::DidDestroyRendererObjects() {
   DCHECK(compositor_client_);
 
   if (registered_with_client_) {
-    input_handler_->SetRootLayerScrollOffsetDelegate(nullptr);
     output_surface_->SetTreeActivationCallback(base::Closure());
     compositor_client_->DidDestroyCompositor(this);
     registered_with_client_ = false;
   }
 
+  // This object is being destroyed, so remove pointers to it.
   begin_frame_source_->SetCompositor(nullptr);
   output_surface_->SetCompositor(nullptr);
+  synchronous_input_handler_proxy_->SetOnlySynchronouslyAnimateRootFlings(
+      nullptr);
 
-  input_handler_ = nullptr;
+  synchronous_input_handler_proxy_ = nullptr;
   begin_frame_source_ = nullptr;
   output_surface_ = nullptr;
   // Don't propogate this signal from one renderer to the next.
@@ -276,9 +273,10 @@ void SynchronousCompositorImpl::PostInvalidate() {
 void SynchronousCompositorImpl::DidChangeRootLayerScrollOffset(
     const gfx::ScrollOffset& root_offset) {
   DCHECK(CalledOnValidThread());
-  if (!input_handler_)
+  if (!synchronous_input_handler_proxy_)
     return;
-  input_handler_->OnRootLayerDelegatedScrollOffsetChanged(root_offset);
+  synchronous_input_handler_proxy_->SynchronouslySetRootScrollOffset(
+      root_offset);
 }
 
 void SynchronousCompositorImpl::SetIsActive(bool is_active) {
diff --git a/content/browser/android/in_process/synchronous_compositor_impl.h b/content/browser/android/in_process/synchronous_compositor_impl.h
index 2f310bd..049fe78 100644
--- a/content/browser/android/in_process/synchronous_compositor_impl.h
+++ b/content/browser/android/in_process/synchronous_compositor_impl.h
@@ -10,7 +10,6 @@
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
 #include "base/memory/scoped_ptr.h"
-#include "cc/input/layer_scroll_offset_delegate.h"
 #include "content/browser/android/in_process/synchronous_compositor_output_surface.h"
 #include "content/common/input/input_event_ack_state.h"
 #include "content/public/browser/android/synchronous_compositor.h"
@@ -38,8 +37,7 @@ struct DidOverscrollParams;
 // This class is created on the main thread but most of the APIs are called
 // from the Compositor thread.
 class SynchronousCompositorImpl
-    : public cc::LayerScrollOffsetDelegate,
-      public SynchronousInputHandler,
+    : public SynchronousInputHandler,
       public SynchronousCompositor,
       public WebContentsUserData<SynchronousCompositorImpl> {
  public:
@@ -55,7 +53,6 @@ class SynchronousCompositorImpl
   void DidInitializeRendererObjects(
       SynchronousCompositorOutputSurface* output_surface,
       SynchronousCompositorExternalBeginFrameSource* begin_frame_source,
-      cc::InputHandler* input_handler,
       SynchronousInputHandlerProxy* synchronous_input_handler_proxy);
   void DidDestroyRendererObjects();
 
@@ -86,8 +83,6 @@ class SynchronousCompositorImpl
 
   // SynchronousInputHandler
   void SetNeedsSynchronousAnimateInput() override;
-
-  // LayerScrollOffsetDelegate
   void UpdateRootLayerState(const gfx::ScrollOffset& total_scroll_offset,
                             const gfx::ScrollOffset& max_scroll_offset,
                             const gfx::SizeF& scrollable_size,
@@ -117,7 +112,6 @@ class SynchronousCompositorImpl
   SynchronousCompositorExternalBeginFrameSource* begin_frame_source_;
   WebContents* contents_;
   const int routing_id_;
-  cc::InputHandler* input_handler_;
   SynchronousInputHandlerProxy* synchronous_input_handler_proxy_;
   bool registered_with_client_;
   bool is_active_;
diff --git a/content/browser/android/in_process/synchronous_compositor_registry.cc b/content/browser/android/in_process/synchronous_compositor_registry.cc
index 84c45a2..d101797 100644
--- a/content/browser/android/in_process/synchronous_compositor_registry.cc
+++ b/content/browser/android/in_process/synchronous_compositor_registry.cc
@@ -107,13 +107,11 @@ void SynchronousCompositorRegistry::UnregisterOutputSurface(
 
 void SynchronousCompositorRegistry::RegisterInputHandler(
     int routing_id,
-    cc::InputHandler* input_handler,
     SynchronousInputHandlerProxy* synchronous_input_handler_proxy) {
   DCHECK(CalledOnValidThread());
-  DCHECK(input_handler);
+  DCHECK(synchronous_input_handler_proxy);
   Entry& entry = entry_map_[routing_id];
-  DCHECK(!entry.input_handler);
-  entry.input_handler = input_handler;
+  DCHECK(!entry.synchronous_input_handler_proxy);
   entry.synchronous_input_handler_proxy = synchronous_input_handler_proxy;
   CheckIsReady(routing_id);
 }
@@ -125,7 +123,7 @@ void SynchronousCompositorRegistry::UnregisterInputHandler(int routing_id) {
 
   if (entry.IsReady())
     UnregisterObjects(routing_id);
-  entry.input_handler = nullptr;
+  entry.synchronous_input_handler_proxy = nullptr;
   RemoveEntryIfNeeded(routing_id);
 }
 
@@ -134,7 +132,7 @@ void SynchronousCompositorRegistry::CheckIsReady(int routing_id) {
   Entry& entry = entry_map_[routing_id];
   if (entry.IsReady()) {
     entry.compositor->DidInitializeRendererObjects(
-        entry.output_surface, entry.begin_frame_source, entry.input_handler,
+        entry.output_surface, entry.begin_frame_source,
         entry.synchronous_input_handler_proxy);
   }
 }
@@ -150,7 +148,7 @@ void SynchronousCompositorRegistry::RemoveEntryIfNeeded(int routing_id) {
   DCHECK(entry_map_.find(routing_id) != entry_map_.end());
   Entry& entry = entry_map_[routing_id];
   if (!entry.compositor && !entry.begin_frame_source && !entry.output_surface &&
-      !entry.input_handler) {
+      !entry.synchronous_input_handler_proxy) {
     entry_map_.erase(routing_id);
   }
 }
@@ -163,11 +161,10 @@ SynchronousCompositorRegistry::Entry::Entry()
     : compositor(nullptr),
       begin_frame_source(nullptr),
       output_surface(nullptr),
-      input_handler(nullptr),
       synchronous_input_handler_proxy(nullptr) {}
 
 bool SynchronousCompositorRegistry::Entry::IsReady() {
-  return compositor && begin_frame_source && output_surface && input_handler &&
+  return compositor && begin_frame_source && output_surface &&
          synchronous_input_handler_proxy;
 }
 
diff --git a/content/browser/android/in_process/synchronous_compositor_registry.h b/content/browser/android/in_process/synchronous_compositor_registry.h
index f84bb0d..f7dc913 100644
--- a/content/browser/android/in_process/synchronous_compositor_registry.h
+++ b/content/browser/android/in_process/synchronous_compositor_registry.h
@@ -41,7 +41,6 @@ class SynchronousCompositorRegistry {
       SynchronousCompositorOutputSurface* output_surface);
   void RegisterInputHandler(
       int routing_id,
-      cc::InputHandler* input_handler,
       SynchronousInputHandlerProxy* synchronous_input_handler_proxy);
   void UnregisterInputHandler(int routing_id);
 
@@ -54,7 +53,6 @@ class SynchronousCompositorRegistry {
     SynchronousCompositorImpl* compositor;
     SynchronousCompositorExternalBeginFrameSource* begin_frame_source;
     SynchronousCompositorOutputSurface* output_surface;
-    cc::InputHandler* input_handler;
     SynchronousInputHandlerProxy* synchronous_input_handler_proxy;
 
     Entry();
diff --git a/content/browser/android/in_process/synchronous_input_event_filter.cc b/content/browser/android/in_process/synchronous_input_event_filter.cc
index c3669af..6645607 100644
--- a/content/browser/android/in_process/synchronous_input_event_filter.cc
+++ b/content/browser/android/in_process/synchronous_input_event_filter.cc
@@ -5,7 +5,6 @@
 #include "content/browser/android/in_process/synchronous_input_event_filter.h"
 
 #include "base/callback.h"
-#include "cc/input/input_handler.h"
 #include "content/browser/android/in_process/synchronous_compositor_impl.h"
 #include "content/browser/android/in_process/synchronous_compositor_registry.h"
 #include "content/public/browser/browser_thread.h"
@@ -48,11 +47,10 @@ void SynchronousInputEventFilter::SetBoundHandlerOnUIThread(
 
 void SynchronousInputEventFilter::DidAddInputHandler(
     int routing_id,
-    cc::InputHandler* input_handler,
     SynchronousInputHandlerProxy* synchronous_input_handler_proxy) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   SynchronousCompositorRegistry::GetInstance()->RegisterInputHandler(
-      routing_id, input_handler, synchronous_input_handler_proxy);
+      routing_id, synchronous_input_handler_proxy);
 }
 
 void SynchronousInputEventFilter::DidRemoveInputHandler(int routing_id) {
diff --git a/content/browser/android/in_process/synchronous_input_event_filter.h b/content/browser/android/in_process/synchronous_input_event_filter.h
index 9174a4d..89feee1 100644
--- a/content/browser/android/in_process/synchronous_input_event_filter.h
+++ b/content/browser/android/in_process/synchronous_input_event_filter.h
@@ -35,7 +35,6 @@ class SynchronousInputEventFilter : public InputHandlerManagerClient {
   void SetBoundHandler(const Handler& handler) override;
   void DidAddInputHandler(
       int routing_id,
-      cc::InputHandler* input_handler,
       SynchronousInputHandlerProxy* synchronous_input_handler_proxy) override;
   void DidRemoveInputHandler(int routing_id) override;
   void DidOverscroll(int routing_id,