Delegate root layer scroll offset to android_webview.

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/lazy_instance.h"
 #include "base/message_loop.h"
+#include "cc/input/layer_scroll_offset_delegate.h"
 #include "content/public/browser/android/synchronous_compositor_client.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/render_process_host.h"
 #include "content/public/browser/render_view_host.h"
 #include "content/renderer/android/synchronous_compositor_factory.h"
+#include "content/renderer/gpu/input_handler_manager.h"
+#include "content/renderer/render_thread_impl.h"
 
 namespace content {
 
 namespace {
 
 int GetInProcessRendererId() {
   content::RenderProcessHost::iterator it =
       content::RenderProcessHost::AllHostsIterator();
   if (it.IsAtEnd()) {
     // There should always be one RPH in single process mode.
     NOTREACHED();
     return 0;
   }
 
   int id = it.GetCurrentValue()->GetID();
   it.Advance();
   DCHECK(it.IsAtEnd());  // Not multiprocess compatible.
   return id;
 }
 
-class SynchronousCompositorFactoryImpl : public SynchronousCompositorFactory {
+class SynchronousCompositorFactoryImpl: public SynchronousCompositorFactory {

[joth, 2013/06/01 02:11:35]

undo edit

[mkosiba (inactive), 2013/06/06 17:55:10]

why? was the space in front of the colon intentional? 

[joth, 2013/06/06 20:19:32]

Of course! We always have a space either side of that colon.

$ git grep " : public" | wc -l
15034
$ git grep "\w: public" | wc -l
106

  public:
   SynchronousCompositorFactoryImpl() {
     SynchronousCompositorFactory::SetInstance(this);
   }
 
   // SynchronousCompositorFactory
   virtual scoped_refptr<base::MessageLoopProxy>
       GetCompositorMessageLoop() OVERRIDE {
     return BrowserThread::GetMessageLoopProxyForThread(BrowserThread::UI);
   }
@@ skipping 23 matching lines @@
   WebContents* contents = WebContents::FromRenderViewHost(rvh);
   if (!contents)
     return NULL;
   return FromWebContents(contents);
 }
 
 SynchronousCompositorImpl::SynchronousCompositorImpl(WebContents* contents)
     : compositor_client_(NULL),
       output_surface_(NULL),
       contents_(contents) {
+  DCHECK(RenderThread::Get()->GetMessageLoop() == base::MessageLoop::current());

[joth, 2013/06/01 02:11:35]

I can't work out why this would be. There's only one call to create this class,
SynchronousCompositorImpl::CreateForWebContents below, and it can only happen on
UI thread (it takes a WebContents* which would be very hard to ever get hold of
on render main thread)

[mkosiba (inactive), 2013/06/06 17:55:10]

I think you misunderstood me about which main thread I was asking when I asked
you over IM whether this class is created on the main thread. I was thinking of
the main renderer thread, you were thinking of the main UI thread :)

[joth, 2013/06/06 20:19:32]

Opps! sorry for confusion.
(I've learnt the new meaning of 'main' thread in verbal conversation, but
obviously I still get tripped up in IM chatting..)

+
+  input_handler_manager_ = RenderThreadImpl::current()->input_handler_manager();
+  // TODO(mkosiba): DCHECK(input_handler_manager_); after Jared's patches land.
 }
 
 SynchronousCompositorImpl::~SynchronousCompositorImpl() {
   if (compositor_client_)
     compositor_client_->DidDestroyCompositor(this);
 }
 
 bool SynchronousCompositorImpl::IsHwReady() {
   DCHECK(CalledOnValidThread());
   DCHECK(output_surface_);
@@ skipping 23 matching lines @@
 
   return output_surface_->DemandDrawHw(view_size, transform, damage_area);
 }
 
 void SynchronousCompositorImpl::DidBindOutputSurface(
       SynchronousCompositorOutputSurface* output_surface) {
   DCHECK(CalledOnValidThread());
   output_surface_ = output_surface;
   if (compositor_client_)
     compositor_client_->DidInitializeCompositor(this);
+
+  if (input_handler_manager_)
+    input_handler_manager_->SetRootLayerScrollDelegate(routing_id_, this);
 }
 
 void SynchronousCompositorImpl::DidDestroySynchronousOutputSurface(
        SynchronousCompositorOutputSurface* output_surface) {
   DCHECK(CalledOnValidThread());
+
+  if (input_handler_manager_)
+    input_handler_manager_->SetRootLayerScrollDelegate(routing_id_, NULL);
+
   // Allow for transient hand-over when two output surfaces may refer to
   // a single delegate.
   if (output_surface_ == output_surface) {
     output_surface_ = NULL;
     if (compositor_client_)
       compositor_client_->DidDestroyCompositor(this);
     compositor_client_ = NULL;
   }
 }
 
 void SynchronousCompositorImpl::SetContinuousInvalidate(bool enable) {
   DCHECK(CalledOnValidThread());
   if (compositor_client_)
     compositor_client_->SetContinuousInvalidate(enable);
 }
 
+void SynchronousCompositorImpl::SetTotalScrollOffset(gfx::Vector2dF new_value) {
+  DCHECK(CalledOnValidThread());
+  if (compositor_client_)
+    compositor_client_->SetTotalRootLayerScrollOffset(new_value);
+}
+
+gfx::Vector2dF SynchronousCompositorImpl::GetTotalScrollOffset() {
+  DCHECK(CalledOnValidThread());
+  if (compositor_client_)
+    return compositor_client_->GetTotalRootLayerScrollOffset();
+  else
+    return gfx::Vector2dF();
+}
+
 // 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);
   }
   if (SynchronousCompositorImpl* instance =
       SynchronousCompositorImpl::FromWebContents(contents)) {
     instance->SetClient(client);
   }
 }
 
 }  // namespace content