Set the minimum timer interval on a per-page basis, and adjust it when

tabs are brought to the foreground and sent to the background.

This CL does not actually increase the background timer interval. That
will be done separately, so that it can easily be reverted without
removing all of the associated code.

BUG=66078
TEST=none (tested manually with minimal test case)

Review URL: http://codereview.chromium.org/6532012

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@75404 0039d316-1c4b-4281-b951-d872f2087c98

7 files changed, 52 insertions, 4 deletions

diff --git a/chrome/renderer/render_view.cc b/chrome/renderer/render_view.cc
index 4357721..48a3f62 100644
--- a/chrome/renderer/render_view.cc
+++ b/chrome/renderer/render_view.cc
@@ -185,6 +185,7 @@
 #include "webkit/glue/site_isolation_metrics.h"
 #include "webkit/glue/webaccessibility.h"
 #include "webkit/glue/webdropdata.h"
+#include "webkit/glue/webkit_constants.h"
 #include "webkit/glue/webkit_glue.h"
 #include "webkit/glue/webmediaplayer_impl.h"
 #include "webkit/plugins/npapi/default_plugin_shared.h"
@@ -5370,29 +5371,41 @@ void RenderView::DidHandleMouseEvent(const WebKit::WebMouseEvent& event) {
   FOR_EACH_OBSERVER(RenderViewObserver, observers_, DidHandleMouseEvent(event));
 }
 
-#if defined(OS_MACOSX)
 void RenderView::OnWasHidden() {
   RenderWidget::OnWasHidden();
 
+  if (webview()) {
+    webview()->settings()->setMinimumTimerInterval(
+        webkit_glue::kBackgroundTabTimerInterval);
+  }
+
+#if defined(OS_MACOSX)
   // Inform plugins that their container is no longer visible.
   std::set<WebPluginDelegateProxy*>::iterator plugin_it;
   for (plugin_it = plugin_delegates_.begin();
        plugin_it != plugin_delegates_.end(); ++plugin_it) {
     (*plugin_it)->SetContainerVisibility(false);
   }
+#endif  // OS_MACOSX
 }
 
 void RenderView::OnWasRestored(bool needs_repainting) {
   RenderWidget::OnWasRestored(needs_repainting);
 
+  if (webview()) {
+    webview()->settings()->setMinimumTimerInterval(
+        webkit_glue::kForegroundTabTimerInterval);
+  }
+
+#if defined(OS_MACOSX)
   // Inform plugins that their container is now visible.
   std::set<WebPluginDelegateProxy*>::iterator plugin_it;
   for (plugin_it = plugin_delegates_.begin();
        plugin_it != plugin_delegates_.end(); ++plugin_it) {
     (*plugin_it)->SetContainerVisibility(true);
   }
-}
 #endif  // OS_MACOSX
+}
 
 void RenderView::OnSetFocus(bool enable) {
   RenderWidget::OnSetFocus(enable);
diff --git a/chrome/renderer/render_view.h b/chrome/renderer/render_view.h
index 7944059..d16012c 100644
--- a/chrome/renderer/render_view.h
+++ b/chrome/renderer/render_view.h
@@ -652,10 +652,8 @@ class RenderView : public RenderWidget,
   virtual void DidHandleKeyEvent();
   virtual void DidHandleMouseEvent(const WebKit::WebMouseEvent& event);
   virtual void OnSetFocus(bool enable);
-#if OS_MACOSX
   virtual void OnWasHidden();
   virtual void OnWasRestored(bool needs_repainting);
-#endif
 
  private:
   // For unit tests.
diff --git a/webkit/glue/webkit_constants.h b/webkit/glue/webkit_constants.h
new file mode 100644
index 0000000..54e7e00
--- /dev/null
+++ b/webkit/glue/webkit_constants.h
@@ -0,0 +1,22 @@
+// Copyright (c) 2011 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.
+
+#ifndef WEBKIT_GLUE_WEBKIT_CONSTANTS_H_
+#define WEBKIT_GLUE_WEBKIT_CONSTANTS_H_
+
+namespace webkit_glue {
+
+// Chromium sets the minimum interval timeout to 4ms, overriding the
+// default of 10ms.  We'd like to go lower, however there are poorly
+// coded websites out there which do create CPU-spinning loops.  Using
+// 4ms prevents the CPU from spinning too busily and provides a balance
+// between CPU spinning and the smallest possible interval timer.
+const double kForegroundTabTimerInterval = 0.004;
+
+// Provides control over the minimum timer interval for background tabs.
+const double kBackgroundTabTimerInterval = 0.004;
+
+} // namespace webkit_glue
+
+#endif  // WEBKIT_GLUE_WEBKIT_CONSTANTS_H_
diff --git a/webkit/glue/webkit_glue.gypi b/webkit/glue/webkit_glue.gypi
index 7060ed2..c3bb964 100644
--- a/webkit/glue/webkit_glue.gypi
+++ b/webkit/glue/webkit_glue.gypi
@@ -422,6 +422,7 @@
         'webdropdata.h',
         'webfileutilities_impl.cc',
         'webfileutilities_impl.h',
+        'webkit_constants.h',
         'webkit_glue.cc',
         'webkit_glue.h',
         'webkitclient_impl.cc',
diff --git a/webkit/glue/webpreferences.cc b/webkit/glue/webpreferences.cc
index 03c87bf..86c40f6 100644
--- a/webkit/glue/webpreferences.cc
+++ b/webkit/glue/webpreferences.cc
@@ -12,6 +12,7 @@
 #include "third_party/WebKit/Source/WebKit/chromium/public/WebString.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/WebURL.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/WebView.h"
+#include "webkit/glue/webkit_constants.h"
 #include "webkit/glue/webkit_glue.h"
 
 using WebKit::WebRuntimeFeatures;
@@ -197,4 +198,7 @@ void WebPreferences::Apply(WebView* web_view) const {
 
   settings->setInteractiveFormValidationEnabled(
       interactive_form_validation_enabled);
+
+  // Tabs start out hidden and are made visible.
+  settings->setMinimumTimerInterval(webkit_glue::kBackgroundTabTimerInterval);
 }
diff --git a/webkit/support/webkit_support.cc b/webkit/support/webkit_support.cc
index 2e893f9..9e850f4 100644
--- a/webkit/support/webkit_support.cc
+++ b/webkit/support/webkit_support.cc
@@ -37,6 +37,7 @@
 #include "third_party/WebKit/Source/WebKit/chromium/public/WebURLError.h"
 #include "webkit/appcache/web_application_cache_host_impl.h"
 #include "webkit/glue/media/video_renderer_impl.h"
+#include "webkit/glue/webkit_constants.h"
 #include "webkit/glue/webkit_glue.h"
 #include "webkit/glue/webkitclient_impl.h"
 #include "webkit/glue/webmediaplayer_impl.h"
@@ -548,4 +549,9 @@ void OpenFileSystem(WebFrame* frame, WebFileSystem::Type type,
   fileSystem->OpenFileSystem(frame, type, size, create, callbacks);
 }
 
+// Timers
+double GetForegroundTabTimerInterval() {
+  return webkit_glue::kForegroundTabTimerInterval;
+}
+
 }  // namespace webkit_support
diff --git a/webkit/support/webkit_support.h b/webkit/support/webkit_support.h
index 30cb885..d145955 100644
--- a/webkit/support/webkit_support.h
+++ b/webkit/support/webkit_support.h
@@ -182,6 +182,10 @@ enum {
     VKEY_F1 = ui::VKEY_F1,
 };
 
+// - Timers
+
+double GetForegroundTabTimerInterval();
+
 }  // namespace webkit_support
 
 #endif  // WEBKIT_SUPPORT_WEBIT_CLIENT_IMPL_H_