Implement active wheel fling transfer via WebCompositorInputHandlerClient

content/renderer/gpu/compositor_thread.cc

Index: content/renderer/gpu/compositor_thread.cc
diff --git a/content/renderer/gpu/compositor_thread.cc b/content/renderer/gpu/compositor_thread.cc
index d4c790c297ff3a5973b22bd3abf1c52fa328617b..287d35a938cffa9834d2378c8f48a27ebbe30bd7 100644
--- a/content/renderer/gpu/compositor_thread.cc
+++ b/content/renderer/gpu/compositor_thread.cc
@@ -6,9 +6,12 @@
 
 #include "base/bind.h"
 #include "content/renderer/gpu/input_event_filter.h"
-#include "third_party/WebKit/Source/WebKit/chromium/public/WebCompositor.h"
-#include "third_party/WebKit/Source/WebKit/chromium/public/WebCompositorClient.h"
+#include "content/public/renderer/render_view.h"
+#include "content/public/renderer/render_view_visitor.h"
+#include "third_party/WebKit/Source/WebKit/chromium/public/WebActiveWheelFlingParameters.h"
+#include "third_party/WebKit/Source/WebKit/chromium/public/WebCompositorInputHandlerClient.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/WebCompositorInputHandler.h"
+#include "third_party/WebKit/Source/WebKit/chromium/public/WebView.h"
 
 using WebKit::WebCompositorInputHandler;
 using WebKit::WebInputEvent;
@@ -16,17 +19,29 @@ using WebKit::WebInputEvent;
 //------------------------------------------------------------------------------
 
 class CompositorThread::InputHandlerWrapper
-    : public WebKit::WebCompositorClient {
+    : public WebKit::WebCompositorInputHandlerClient {
  public:
   InputHandlerWrapper(CompositorThread* compositor_thread,
                       int routing_id,
-                      WebKit::WebCompositorInputHandler* input_handler)
+                      WebKit::WebCompositorInputHandler* input_handler,
+                      scoped_refptr<base::MessageLoopProxy> main_loop)
       : compositor_thread_(compositor_thread),
         routing_id_(routing_id),
-        input_handler_(input_handler) {
+        input_handler_(input_handler),
+        main_loop_(main_loop),
+        render_view_finder_(routing_id) {
     input_handler_->setClient(this);
   }
 
+  virtual void transferActiveWheelFlingAnimation(
+      const WebKit::WebActiveWheelFlingParameters& params) {
+    main_loop_->PostTask(
+        FROM_HERE,
+        base::Bind(&CompositorThread::InputHandlerWrapper
+                   ::TransferActiveWheelFlingAnimation,
+            base::Unretained(this), params));
+  }
+
   virtual ~InputHandlerWrapper() {
     input_handler_->setClient(NULL);
   }
@@ -36,7 +51,7 @@ class CompositorThread::InputHandlerWrapper
     return input_handler_;
   }
 
-  // WebCompositorClient methods:
+  // WebCompositorInputHandlerClient methods:
 
   virtual void willShutdown() {
     compositor_thread_->RemoveInputHandler(routing_id_);
@@ -51,9 +66,46 @@ class CompositorThread::InputHandlerWrapper
   }
 
  private:
+  // TODO(jamesr): There's got to be a better way to do this. Do we have a map
+  // from routing_id -> RenderView / RenderViewImpl somewhere?
+  class FindRenderViewByRoutingIDVisitor : public content::RenderViewVisitor {
+   public:
+    explicit FindRenderViewByRoutingIDVisitor(int routing_id)
+        : routing_id_(routing_id) ,
+          render_view_(NULL) {
+    }
+
+    content::RenderView* FindRenderView() {
+      if (!render_view_)
+        content::RenderView::ForEach(this);
+      return render_view_;
+    }
+
+    virtual bool Visit(content::RenderView* render_view) OVERRIDE {
+      if (render_view->GetRoutingID() == routing_id_)
+        return false;
+      return true;
+    }
+
+   private:
+    int routing_id_;
+    // We will always destroy the CompositorWrapper through

[jamesr, 2012/03/21 14:38:31]

note: I haven't fully convinced myself that this is true. a careful analysis of
the lifetimes here would be really helpful

+    // CompositorThread::RemoveCompositor before the view goes away, so it's
+    // safe to stash a raw pointer here.
+    content::RenderView* render_view_;
+  };
+
+  void TransferActiveWheelFlingAnimation(
+      WebKit::WebActiveWheelFlingParameters params) {
+    render_view_finder_.FindRenderView()->
+        GetWebView()->transferActiveWheelFlingAnimation(params);
+  }
+
   CompositorThread* compositor_thread_;
   int routing_id_;
   WebKit::WebCompositorInputHandler* input_handler_;
+  scoped_refptr<base::MessageLoopProxy> main_loop_;
+  FindRenderViewByRoutingIDVisitor render_view_finder_;
 
   DISALLOW_COPY_AND_ASSIGN(InputHandlerWrapper);
 };
@@ -77,13 +129,22 @@ IPC::ChannelProxy::MessageFilter* CompositorThread::GetMessageFilter() const {
 }
 
 void CompositorThread::AddInputHandler(int routing_id, int input_handler_id) {
-  if (thread_.message_loop() != MessageLoop::current()) {
-    thread_.message_loop()->PostTask(
-        FROM_HERE,
-        base::Bind(&CompositorThread::AddInputHandler, base::Unretained(this),
-                   routing_id, input_handler_id));
-    return;
-  }
+  DCHECK_NE(thread_.message_loop(), MessageLoop::current());
+
+  thread_.message_loop()->PostTask(
+      FROM_HERE,
+      base::Bind(&CompositorThread::AddInputHandlerOnCompositorThread,
+                 base::Unretained(this),
+                 routing_id,
+                 input_handler_id,
+                 base::MessageLoopProxy::current()));
+}
+
+void CompositorThread::AddInputHandlerOnCompositorThread(
+    int routing_id, int input_handler_id,
+    scoped_refptr<base::MessageLoopProxy> main_loop) {
+
+  DCHECK_EQ(thread_.message_loop(), MessageLoop::current());
 
   WebCompositorInputHandler* input_handler =
       WebCompositorInputHandler::fromIdentifier(input_handler_id);
@@ -100,11 +161,12 @@ void CompositorThread::AddInputHandler(int routing_id, int input_handler_id) {
 
   filter_->AddRoute(routing_id);
   input_handlers_[routing_id] =
-      make_linked_ptr(new InputHandlerWrapper(this, routing_id, input_handler));
+      make_linked_ptr(new InputHandlerWrapper(this,
+          routing_id, input_handler, main_loop));
 }
 
 void CompositorThread::RemoveInputHandler(int routing_id) {
-  DCHECK(thread_.message_loop() == MessageLoop::current());
+  DCHECK_EQ(MessageLoop::current(), thread_.message_loop());
 
   filter_->RemoveRoute(routing_id);
   input_handlers_.erase(routing_id);