Stop spamming delayed tasks on each input event.

R=mbelshe
BUG=2693

Review URL: http://codereview.chromium.org/4262

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@2609 0039d316-1c4b-4281-b951-d872f2087c98

4 files changed, 61 insertions, 28 deletions

diff --git a/base/timer.h b/base/timer.h
index 32adbf1..5361130 100644
--- a/base/timer.h
+++ b/base/timer.h
@@ -66,6 +66,13 @@ class BaseTimer_Helper {
     return delayed_task_ != NULL;
   }
 
+  // Returns the current delay for this timer.  May only call this method when
+  // the timer is running!
+  TimeDelta GetCurrentDelay() const {
+    DCHECK(IsRunning());
+    return delayed_task_->delay_;
+  }
+
  protected:
   BaseTimer_Helper() : delayed_task_(NULL) {}
 
diff --git a/chrome/browser/render_view_host.cc b/chrome/browser/render_view_host.cc
index 8c95e07..27b25c9 100644
--- a/chrome/browser/render_view_host.cc
+++ b/chrome/browser/render_view_host.cc
@@ -233,7 +233,7 @@ void RenderViewHost::FirePageBeforeUnload() {
     // Start the hang monitor in case the renderer hangs in the beforeunload
     // handler.
     is_waiting_for_unload_ack_ = true;
-    StartHangMonitorTimeout(kUnloadTimeoutMS);
+    StartHangMonitorTimeout(TimeDelta::FromMilliseconds(kUnloadTimeoutMS));
     Send(new ViewMsg_ShouldClose(routing_id_));
   } else {
     // This RenderViewHost doesn't have a live renderer, so just skip running
@@ -245,7 +245,7 @@ void RenderViewHost::FirePageBeforeUnload() {
 void RenderViewHost::FirePageUnload() {
   // Start the hang monitor in case the renderer hangs in the unload handler.
   is_waiting_for_unload_ack_ = true;
-  StartHangMonitorTimeout(kUnloadTimeoutMS);
+  StartHangMonitorTimeout(TimeDelta::FromMilliseconds(kUnloadTimeoutMS));
   ClosePage(site_instance()->process_host_id(), 
             routing_id());
 }
@@ -487,7 +487,7 @@ void RenderViewHost::JavaScriptMessageBoxClosed(IPC::Message* reply_msg,
                                                 bool success,
                                                 const std::wstring& prompt) {
   if (is_waiting_for_unload_ack_)
-    StartHangMonitorTimeout(kUnloadTimeoutMS);
+    StartHangMonitorTimeout(TimeDelta::FromMilliseconds(kUnloadTimeoutMS));
 
   if (--modal_dialog_count_ == 0)
     ResetEvent(modal_dialog_event_.Get());
@@ -498,7 +498,7 @@ void RenderViewHost::JavaScriptMessageBoxClosed(IPC::Message* reply_msg,
 void RenderViewHost::ModalHTMLDialogClosed(IPC::Message* reply_msg,
                                            const std::string& json_retval) {
   if (is_waiting_for_unload_ack_)
-    StartHangMonitorTimeout(kUnloadTimeoutMS);
+    StartHangMonitorTimeout(TimeDelta::FromMilliseconds(kUnloadTimeoutMS));
 
   if (--modal_dialog_count_ == 0)
     ResetEvent(modal_dialog_event_.Get());
diff --git a/chrome/browser/render_widget_host.cc b/chrome/browser/render_widget_host.cc
index 34e9c26..449b194 100644
--- a/chrome/browser/render_widget_host.cc
+++ b/chrome/browser/render_widget_host.cc
@@ -273,7 +273,6 @@ RenderWidgetHost::RenderWidgetHost(RenderProcessHost* process, int routing_id)
       is_hidden_(false),
       suppress_view_updating_(false),
       needs_repainting_on_restore_(false),
-      hung_renderer_factory_(this),
       is_unresponsive_(false),
       view_being_painted_(false),
       repaint_ack_pending_(false) {
@@ -630,7 +629,7 @@ void RenderWidgetHost::ForwardInputEvent(const WebInputEvent& input_event,
   // any input event cancels a pending mouse move event
   next_mouse_move_.reset();
 
-  StartHangMonitorTimeout(kHungRendererDelayMs);
+  StartHangMonitorTimeout(TimeDelta::FromMilliseconds(kHungRendererDelayMs));
 }
 
 void RenderWidgetHost::Shutdown() {
@@ -673,7 +672,19 @@ void RenderWidgetHost::Destroy() {
   delete this;
 }
 
-void RenderWidgetHost::RendererIsUnresponsive() {
+void RenderWidgetHost::CheckRendererIsUnresponsive() {
+  // If we received a call to StopHangMonitorTimeout.
+  if (time_when_considered_hung_.is_null())
+    return;
+
+  // If we have not waited long enough, then wait some more.
+  Time now = Time::Now();
+  if (now < time_when_considered_hung_) {
+    StartHangMonitorTimeout(time_when_considered_hung_ - now);
+    return;
+  }
+
+  // OK, looks like we have a hung renderer!
   NotificationService::current()->Notify(NOTIFY_RENDERER_PROCESS_HANG,
                                          Source<RenderWidgetHost>(this),
                                          NotificationService::NoDetails());
@@ -788,19 +799,31 @@ void RenderWidgetHost::ScrollRect(HANDLE bitmap, const gfx::Rect& bitmap_rect,
 }
 
 void RenderWidgetHost::RestartHangMonitorTimeout() {
-  hung_renderer_factory_.RevokeAll();
-  StartHangMonitorTimeout(kHungRendererDelayMs);
+  StartHangMonitorTimeout(TimeDelta::FromMilliseconds(kHungRendererDelayMs));
 }
 
 void RenderWidgetHost::StopHangMonitorTimeout() {
-  hung_renderer_factory_.RevokeAll();
+  time_when_considered_hung_ = Time();
   RendererIsResponsive();
+
+  // We do not bother to stop the hung_renderer_timer_ here in case it will be
+  // started again shortly, which happens to be the common use case.
 }
 
-void RenderWidgetHost::StartHangMonitorTimeout(int delay) {
-  MessageLoop::current()->PostDelayedTask(FROM_HERE,
-        hung_renderer_factory_.NewRunnableMethod(
-            &RenderWidgetHost::RendererIsUnresponsive), delay);
+void RenderWidgetHost::StartHangMonitorTimeout(TimeDelta delay) {
+  time_when_considered_hung_ = Time::Now() + delay;
+
+  // If we already have a timer that will expire at or before the given delay,
+  // then we have nothing more to do now.
+  if (hung_renderer_timer_.IsRunning() &&
+      hung_renderer_timer_.GetCurrentDelay() <= delay)
+    return;
+
+  // Either the timer is not yet running, or we need to adjust the timer to
+  // fire sooner.
+  hung_renderer_timer_.Stop();
+  hung_renderer_timer_.Start(delay, this,
+      &RenderWidgetHost::CheckRendererIsUnresponsive);
 }
 
 void RenderWidgetHost::RendererExited() {
diff --git a/chrome/browser/render_widget_host.h b/chrome/browser/render_widget_host.h
index 0db4dbd..fd542e7 100644
--- a/chrome/browser/render_widget_host.h
+++ b/chrome/browser/render_widget_host.h
@@ -2,13 +2,13 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#ifndef CHROME_BROWSER_RENDER_WIDGET_HOST_H__
-#define CHROME_BROWSER_RENDER_WIDGET_HOST_H__
+#ifndef CHROME_BROWSER_RENDER_WIDGET_HOST_H_
+#define CHROME_BROWSER_RENDER_WIDGET_HOST_H_
 
 #include <windows.h>
 
-#include "base/task.h"
 #include "base/gfx/size.h"
+#include "base/timer.h"
 #include "chrome/common/ipc_channel.h"
 
 namespace gfx {
@@ -180,11 +180,11 @@ class RenderWidgetHost : public IPC::Channel::Listener {
   // javascript call.
   virtual bool CanBlur() const { return true; }
 
-  // Restart the active hang monitor timeout. Clears all existing timeouts
-  // and starts with a new one.
-  // This can be because the renderer has become active, the tab is being
-  // hidden, or the user has chosen to wait some more to give the tab a chance
-  // to become active and we don't want to display a warning too soon.
+  // Restart the active hang monitor timeout. Clears all existing timeouts and
+  // starts with a new one.  This can be because the renderer has become
+  // active, the tab is being hidden, or the user has chosen to wait some more
+  // to give the tab a chance to become active and we don't want to display a
+  // warning too soon.
   void RestartHangMonitorTimeout();
   
   // Stops all existing hang monitor timeouts and assumes the renderer is
@@ -194,7 +194,7 @@ class RenderWidgetHost : public IPC::Channel::Listener {
   // Starts a hang monitor timeout. If there's already a hang monitor timeout
   // the new one will only fire if it has a shorter delay than the time
   // left on the existing timeouts.
-  void StartHangMonitorTimeout(int delay);
+  void StartHangMonitorTimeout(TimeDelta delay);
 
   // Called when we receive a notification indicating that the renderer
   // process has gone.
@@ -250,7 +250,7 @@ class RenderWidgetHost : public IPC::Channel::Listener {
   // Callbacks for notification when the renderer becomes unresponsive to user
   // input events, and subsequently responsive again. The delegate can use
   // these notifications to show a warning.
-  void RendererIsUnresponsive();
+  void CheckRendererIsUnresponsive();
   virtual void NotifyRendererUnresponsive() {}
   void RendererIsResponsive();
   virtual void NotifyRendererResponsive() {}
@@ -298,8 +298,12 @@ class RenderWidgetHost : public IPC::Channel::Listener {
   // itself, a paint message could already be in flight at that point.
   bool needs_repainting_on_restore_;
 
-  // The following factory is used to detect a hung renderer
-  ScopedRunnableMethodFactory<RenderWidgetHost> hung_renderer_factory_;
+  // The following value indicates a time in the future when we would consider
+  // the renderer hung if it does not generate an appropriate response message.
+  Time time_when_considered_hung_;
+
+  // This timer runs to check if time_when_considered_hung_ has past.
+  base::OneShotTimer<RenderWidgetHost> hung_renderer_timer_;
 
   // This is true if the renderer is currently unresponsive.
   bool is_unresponsive_;
@@ -359,5 +363,4 @@ class RenderWidgetHost::PaintObserver {
   virtual void RenderWidgetHostDidPaint(RenderWidgetHost* rwh) = 0;
 };
 
-#endif  // #ifndef CHROME_BROWSER_RENDER_WIDGET_HOST_H__
-
+#endif  // #ifndef CHROME_BROWSER_RENDER_WIDGET_HOST_H_