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

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@254305 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 24 insertions, 9 deletions

diff --git a/content/renderer/renderer_webkitplatformsupport_impl.cc b/content/renderer/renderer_webkitplatformsupport_impl.cc
index c19b50a..3118a12 100644
--- a/content/renderer/renderer_webkitplatformsupport_impl.cc
+++ b/content/renderer/renderer_webkitplatformsupport_impl.cc
@@ -77,18 +77,20 @@
 #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>
 
@@ -98,13 +100,18 @@
 #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;
@@ -211,7 +218,8 @@ 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);
@@ -883,6 +891,13 @@ 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();