Merge 254305 "After Aura copied the original Linux scrollbar beh..."

> After Aura copied the original Linux scrollbar behvaior, it never got updated
> with Windows-specific native behaviors from ScrollbarThemeWin.cpp:
> 
> * Snap the scrollbar back to its drag origin when dragged too far off the track.
> This code matches the old code we had for years and also matches my Win 7
> native scrollbars pixel-for-pixel.
> 
> * Don't jump the scroll thumb to the mouse cursor on a middle-click, only on a
> shift-click. Middle-click must be a GTK-ism.
> 
> This is the Chrome side of the changes to re-add this behavior.
> 
> BUG=337919
> TEST=Drag a scroll thumb to somewhere in the track, then without releasing, move the mouse far away from the track. The scroll thumb should snap back to the scroll origin.
> R=avi@chromium.org
> 
> Review URL: https://codereview.chromium.org/175903002

TBR=pkasting@chromium.org

Review URL: https://codereview.chromium.org/188083003

git-svn-id: svn://svn.chromium.org/chrome/branches/1847/src@255163 0039d316-1c4b-4281-b951-d872f2087c98

8 files changed, 184 insertions, 20 deletions

diff --git a/content/content_renderer.gypi b/content/content_renderer.gypi
index 30c102a..ee69c72 100644
--- a/content/content_renderer.gypi
+++ b/content/content_renderer.gypi
@@ -523,6 +523,10 @@
     'renderer/webgraphicscontext3d_provider_impl.h',
     'renderer/webpublicsuffixlist_impl.cc',
     'renderer/webpublicsuffixlist_impl.h',
+    'renderer/webscrollbarbehavior_impl_gtkoraura.cc',
+    'renderer/webscrollbarbehavior_impl_gtkoraura.h',
+    'renderer/webscrollbarbehavior_impl_mac.mm',
+    'renderer/webscrollbarbehavior_impl_mac.h',
     'renderer/websharedworker_proxy.cc',
     'renderer/websharedworker_proxy.h',
   ],
@@ -547,6 +551,13 @@
     ['OS=="mac"', {
       'sources!': [
         'common/process_watcher_posix.cc',
+        'renderer/webscrollbarbehavior_impl_gtkoraura.cc',
+        'renderer/webscrollbarbehavior_impl_gtkoraura.h',
+      ],
+    }, {
+      'sources!': [
+        'renderer/webscrollbarbehavior_impl_mac.mm',
+        'renderer/webscrollbarbehavior_impl_mac.h',
       ],
     }],
     ['OS=="win" and win_use_allocator_shim==1', {
diff --git a/content/renderer/render_thread_impl.cc b/content/renderer/render_thread_impl.cc
index e27d04f..96f4904 100644
--- a/content/renderer/render_thread_impl.cc
+++ b/content/renderer/render_thread_impl.cc
@@ -115,6 +115,20 @@
 #include "webkit/child/worker_task_runner.h"
 #include "webkit/renderer/compositor_bindings/web_external_bitmap_impl.h"
 
+#if defined(OS_ANDROID)
+#include <cpu-features.h>
+#include "content/renderer/android/synchronous_compositor_factory.h"
+#include "content/renderer/media/android/renderer_demuxer_android.h"
+#endif
+
+#if defined(OS_MACOSX)
+#include "content/renderer/webscrollbarbehavior_impl_mac.h"
+#endif
+
+#if defined(OS_POSIX)
+#include "ipc/ipc_channel_posix.h"
+#endif
+
 #if defined(OS_WIN)
 #include <windows.h>
 #include <objbase.h>
@@ -124,16 +138,6 @@
 #include "content/child/npapi/np_channel_base.h"
 #endif
 
-#if defined(OS_POSIX)
-#include "ipc/ipc_channel_posix.h"
-#endif
-
-#if defined(OS_ANDROID)
-#include <cpu-features.h>
-#include "content/renderer/android/synchronous_compositor_factory.h"
-#include "content/renderer/media/android/renderer_demuxer_android.h"
-#endif
-
 #if defined(ENABLE_PLUGINS)
 #include "content/renderer/npapi/plugin_channel_host.h"
 #endif
@@ -1321,9 +1325,11 @@ void RenderThreadImpl::OnUpdateScrollbarTheme(
     bool jump_on_track_click,
     blink::ScrollerStyle preferred_scroller_style,
     bool redraw) {
+  static_cast<WebScrollbarBehaviorImpl*>(
+      webkit_platform_support_->scrollbarBehavior())->set_jump_on_track_click(
+          jump_on_track_click);
   blink::WebScrollbarTheme::updateScrollbars(initial_button_delay,
                                              autoscroll_button_delay,
-                                             jump_on_track_click,
                                              preferred_scroller_style,
                                              redraw);
 }
diff --git a/content/renderer/renderer_webkitplatformsupport_impl.cc b/content/renderer/renderer_webkitplatformsupport_impl.cc
index a92c3ae..3d6f55e 100644
--- a/content/renderer/renderer_webkitplatformsupport_impl.cc
+++ b/content/renderer/renderer_webkitplatformsupport_impl.cc
@@ -75,18 +75,20 @@
 #include "webkit/common/gpu/context_provider_web_context.h"
 #include "webkit/common/quota/quota_types.h"
 
-#if defined(OS_WIN)
-#include "content/common/child_process_messages.h"
-#include "third_party/WebKit/public/platform/win/WebSandboxSupport.h"
+#if defined(OS_ANDROID)
+#include "content/renderer/media/android/audio_decoder_android.h"
 #endif
 
 #if defined(OS_MACOSX)
 #include "content/common/mac/font_descriptor.h"
 #include "content/common/mac/font_loader.h"
+#include "content/renderer/webscrollbarbehavior_impl_mac.h"
 #include "third_party/WebKit/public/platform/mac/WebSandboxSupport.h"
 #endif
 
-#if defined(OS_POSIX) && !defined(OS_MACOSX) && !defined(OS_ANDROID)
+#if defined(OS_POSIX)
+#include "base/file_descriptor_posix.h"
+#if !defined(OS_MACOSX) && !defined(OS_ANDROID)
 #include <map>
 #include <string>
 
@@ -96,13 +98,18 @@
 #include "third_party/WebKit/public/platform/linux/WebSandboxSupport.h"
 #include "third_party/icu/source/common/unicode/utf16.h"
 #endif
+#endif
 
-#if defined(OS_POSIX)
-#include "base/file_descriptor_posix.h"
+#if defined(OS_WIN)
+#include "content/common/child_process_messages.h"
+#include "third_party/WebKit/public/platform/win/WebSandboxSupport.h"
 #endif
 
-#if defined(OS_ANDROID)
-#include "content/renderer/media/android/audio_decoder_android.h"
+#if defined(TOOLKIT_GTK) || defined(USE_AURA)
+#include "content/renderer/webscrollbarbehavior_impl_gtkoraura.h"
+#elif !defined(OS_MACOSX)
+#include "third_party/WebKit/public/platform/WebScrollbarBehavior.h"
+#define WebScrollbarBehaviorImpl blink::WebScrollbarBehavior
 #endif
 
 using blink::Platform;
@@ -206,7 +213,8 @@ RendererWebKitPlatformSupportImpl::RendererWebKitPlatformSupportImpl()
       mime_registry_(new RendererWebKitPlatformSupportImpl::MimeRegistry),
       sudden_termination_disables_(0),
       plugin_refresh_allowed_(true),
-      child_thread_loop_(base::MessageLoopProxy::current()) {
+      child_thread_loop_(base::MessageLoopProxy::current()),
+      web_scrollbar_behavior_(new WebScrollbarBehaviorImpl) {
   if (g_sandbox_enabled && sandboxEnabled()) {
     sandbox_support_.reset(
         new RendererWebKitPlatformSupportImpl::SandboxSupport);
@@ -843,6 +851,13 @@ void RendererWebKitPlatformSupportImpl::screenColorProfile(
 
 //------------------------------------------------------------------------------
 
+blink::WebScrollbarBehavior*
+    RendererWebKitPlatformSupportImpl::scrollbarBehavior() {
+  return web_scrollbar_behavior_.get();
+}
+
+//------------------------------------------------------------------------------
+
 WebBlobRegistry* RendererWebKitPlatformSupportImpl::blobRegistry() {
   // blob_registry_ can be NULL when running some tests.
   return blob_registry_.get();
diff --git a/content/renderer/renderer_webkitplatformsupport_impl.h b/content/renderer/renderer_webkitplatformsupport_impl.h
index 45f2924..f9ab0b3 100644
--- a/content/renderer/renderer_webkitplatformsupport_impl.h
+++ b/content/renderer/renderer_webkitplatformsupport_impl.h
@@ -91,6 +91,7 @@ class CONTENT_EXPORT RendererWebKitPlatformSupportImpl
                              blink::WebPluginListBuilder* builder);
   virtual blink::WebPublicSuffixList* publicSuffixList();
   virtual void screenColorProfile(blink::WebVector<char>* to_profile);
+  virtual blink::WebScrollbarBehavior* scrollbarBehavior();
   virtual blink::WebIDBFactory* idbFactory();
   virtual blink::WebFileSystem* fileSystem();
   virtual bool canAccelerate2dCanvas();
@@ -218,6 +219,8 @@ class CONTENT_EXPORT RendererWebKitPlatformSupportImpl
 
   scoped_ptr<WebCryptoImpl> web_crypto_;
 
+  scoped_ptr<blink::WebScrollbarBehavior> web_scrollbar_behavior_;
+
   DISALLOW_COPY_AND_ASSIGN(RendererWebKitPlatformSupportImpl);
 };
 
diff --git a/content/renderer/webscrollbarbehavior_impl_gtkoraura.cc b/content/renderer/webscrollbarbehavior_impl_gtkoraura.cc
new file mode 100644
index 0000000..8398858
--- /dev/null
+++ b/content/renderer/webscrollbarbehavior_impl_gtkoraura.cc
@@ -0,0 +1,51 @@
+// Copyright 2014 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/renderer/webscrollbarbehavior_impl_gtkoraura.h"
+
+#include "third_party/WebKit/public/platform/WebPoint.h"
+#include "third_party/WebKit/public/platform/WebRect.h"
+
+namespace content {
+
+bool WebScrollbarBehaviorImpl::shouldCenterOnThumb(
+      blink::WebScrollbarBehavior::Button mouseButton,
+      bool shiftKeyPressed,
+      bool altKeyPressed) {
+#if defined(TOOLKIT_GTK) || (defined(OS_LINUX) && !defined(OS_CHROMEOS))
+  if (mouseButton == blink::WebScrollbarBehavior::ButtonMiddle)
+    return true;
+#endif
+  return (mouseButton == blink::WebScrollbarBehavior::ButtonLeft) &&
+      shiftKeyPressed;
+}
+
+bool WebScrollbarBehaviorImpl::shouldSnapBackToDragOrigin(
+    const blink::WebPoint& eventPoint,
+    const blink::WebRect& scrollbarRect,
+    bool isHorizontal) {
+#if defined(TOOLKIT_GTK)
+  return false;
+#endif
+
+  // Constants used to figure the drag rect outside which we should snap the
+  // scrollbar thumb back to its origin. These calculations are based on
+  // observing the behavior of the MSVC8 main window scrollbar + some
+  // guessing/extrapolation.
+  static const int kOffEndMultiplier = 3;
+  static const int kOffSideMultiplier = 8;
+
+  // Find the rect within which we shouldn't snap, by expanding the track rect
+  // in both dimensions.
+  gfx::Rect noSnapRect(scrollbarRect);
+  const int thickness = isHorizontal ? noSnapRect.height() : noSnapRect.width();
+  noSnapRect.Inset(
+      (isHorizontal ? kOffEndMultiplier : kOffSideMultiplier) * -thickness,
+      (isHorizontal ? kOffSideMultiplier : kOffEndMultiplier) * -thickness);
+
+  // We should snap iff the event is outside our calculated rect.
+  return !noSnapRect.Contains(eventPoint);
+}
+
+}  // namespace content
\ No newline at end of file
diff --git a/content/renderer/webscrollbarbehavior_impl_gtkoraura.h b/content/renderer/webscrollbarbehavior_impl_gtkoraura.h
new file mode 100644
index 0000000..7d681d3
--- /dev/null
+++ b/content/renderer/webscrollbarbehavior_impl_gtkoraura.h
@@ -0,0 +1,25 @@
+// Copyright 2014 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 CONTENT_CHILD_WEBSCROLLBARBEHAVIOR_IMPL_GTKORAURA_H_
+#define CONTENT_CHILD_WEBSCROLLBARBEHAVIOR_IMPL_GTKORAURA_H_
+
+#include "third_party/WebKit/public/platform/WebScrollbarBehavior.h"
+
+namespace content {
+
+class WebScrollbarBehaviorImpl : public blink::WebScrollbarBehavior {
+ public:
+  virtual bool shouldCenterOnThumb(
+      blink::WebScrollbarBehavior::Button mouseButton,
+      bool shiftKeyPressed,
+      bool altKeyPressed);
+  virtual bool shouldSnapBackToDragOrigin(const blink::WebPoint& eventPoint,
+                                          const blink::WebRect& scrollbarRect,
+                                          bool isHorizontal);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_CHILD_WEBSCROLLBARBEHAVIOR_IMPL_GTKORAURA_H_
diff --git a/content/renderer/webscrollbarbehavior_impl_mac.h b/content/renderer/webscrollbarbehavior_impl_mac.h
new file mode 100644
index 0000000..5632299
--- /dev/null
+++ b/content/renderer/webscrollbarbehavior_impl_mac.h
@@ -0,0 +1,32 @@
+// Copyright 2014 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 CONTENT_CHILD_WEBSCROLLBARBEHAVIOR_IMPL_MAC_H_
+#define CONTENT_CHILD_WEBSCROLLBARBEHAVIOR_IMPL_MAC_H_
+
+#include "third_party/WebKit/public/platform/WebScrollbarBehavior.h"
+
+namespace content {
+
+class WebScrollbarBehaviorImpl : public blink::WebScrollbarBehavior {
+ public:
+  WebScrollbarBehaviorImpl();
+
+  virtual bool shouldCenterOnThumb(
+      blink::WebScrollbarBehavior::Button mouseButton,
+      bool shiftKeyPressed,
+      bool altKeyPressed);
+
+  void set_jump_on_track_click(bool jump_on_track_click) {
+    jump_on_track_click_ = jump_on_track_click;
+  }
+
+ private:
+  // The current value of AppleScrollerPagingBehavior from NSUserDefaults.
+  bool jump_on_track_click_;
+};
+
+}  // namespace content
+
+#endif  // CONTENT_CHILD_WEBSCROLLBARBEHAVIOR_IMPL_MAC_H_
diff --git a/content/renderer/webscrollbarbehavior_impl_mac.mm b/content/renderer/webscrollbarbehavior_impl_mac.mm
new file mode 100644
index 0000000..9f83f8a
--- /dev/null
+++ b/content/renderer/webscrollbarbehavior_impl_mac.mm
@@ -0,0 +1,21 @@
+// Copyright 2014 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/renderer/webscrollbarbehavior_impl_mac.h"
+
+namespace content {
+
+WebScrollbarBehaviorImpl::WebScrollbarBehaviorImpl()
+    : jump_on_track_click_(false) {
+}
+
+bool WebScrollbarBehaviorImpl::shouldCenterOnThumb(
+      blink::WebScrollbarBehavior::Button mouseButton,
+      bool shiftKeyPressed,
+      bool altKeyPressed) {
+  return (mouseButton == blink::WebScrollbarBehavior::ButtonLeft) &&
+      (jump_on_track_click_ != altKeyPressed);
+}
+
+}  // namespace content