8 files changed, 77 insertions, 3 deletions
diff --git a/chrome/browser/browser_window_cocoa.mm b/chrome/browser/browser_window_cocoa.mm
index baee161..e61bea443 100644
--- a/chrome/browser/browser_window_cocoa.mm
+++ b/chrome/browser/browser_window_cocoa.mm
@@ -99,10 +99,16 @@ bool BrowserWindowCocoa::IsFullscreen() const {
   return false;
 }
 
+@interface NSWindow(OSInternals)
+- (NSRect)_growBoxRect;
+@end
+
 gfx::Rect BrowserWindowCocoa::GetRootWindowResizerRect() const {
-  // TODO(pinkerton): fill this in so scrollbars go in the correct places
-  NOTIMPLEMENTED();
-  return gfx::Rect();
+  NSRect windowRect = [window_ _growBoxRect];
+  // convert from window coordinates to the coordinates of the currently
+  // selected tab. |tabRect| will already be flipped into WebKit coordinates.
+  NSRect tabRect = [controller_ selectedTabGrowBoxFromWindowGrowBox:windowRect];
+  return gfx::Rect(NSRectToCGRect(tabRect));
 }
 
 LocationBar* BrowserWindowCocoa::GetLocationBar() const {
diff --git a/chrome/browser/browser_window_controller.h b/chrome/browser/browser_window_controller.h
index 5601b3f..9428cd3 100644
--- a/chrome/browser/browser_window_controller.h
+++ b/chrome/browser/browser_window_controller.h
@@ -55,6 +55,11 @@ class BrowserWindow;
 // Sets whether or not the current page in the frontmost tab is bookmarked.
 - (void)setStarredState:(BOOL)isStarred;
 
+// Return the rect, in WebKit coordinates (flipped), of the window's grow box
+// in the coordinate system of the content area of the currently selected tab.
+// |windowGrowBox| needs to be in the window's coordinate system.
+- (NSRect)selectedTabGrowBoxFromWindowGrowBox:(NSRect)windowGrowBox;
+
 @end
 
 #endif  // CHROME_BROWSER_BROWSER_WINDOW_CONTROLLER_H_
diff --git a/chrome/browser/browser_window_controller.mm b/chrome/browser/browser_window_controller.mm
index 282193b..eade6e2 100644
--- a/chrome/browser/browser_window_controller.mm
+++ b/chrome/browser/browser_window_controller.mm
@@ -145,4 +145,12 @@
   [tabStripController_ setStarredState:isStarred];
 }
 
+// Return the rect, in WebKit coordinates (flipped), of the window's grow box
+// in the coordinate system of the content area of the currently selected tab.
+// |windowGrowBox| needs to be in the window's coordinate system.
+- (NSRect)selectedTabGrowBoxFromWindowGrowBox:(NSRect)windowGrowBox {
+  return [tabStripController_ 
+              selectedTabGrowBoxFromWindowGrowBox:windowGrowBox];
+}
+
 @end
diff --git a/chrome/browser/cocoa/tab_contents_controller.h b/chrome/browser/cocoa/tab_contents_controller.h
index 4d205bb..20d9a38 100644
--- a/chrome/browser/cocoa/tab_contents_controller.h
+++ b/chrome/browser/cocoa/tab_contents_controller.h
@@ -68,6 +68,11 @@ class TabStripModel;
 // Sets whether or not the current page in the frontmost tab is bookmarked.
 - (void)setStarredState:(BOOL)isStarred;
 
+// Return the rect, in WebKit coordinates (flipped), of the window's grow box
+// in the coordinate system of the content area of this tab.
+// |windowGrowBox| needs to be in the window's coordinate system.
+- (NSRect)growBoxFromWindowGrowBox:(NSRect)windowGrowBox;
+
 @end
 
 #endif  // CHROME_BROWSER_COCOA_TAB_COTNENTS_CONTROLLER_H_
diff --git a/chrome/browser/cocoa/tab_contents_controller.mm b/chrome/browser/cocoa/tab_contents_controller.mm
index 4b8eb8b..5d62716 100644
--- a/chrome/browser/cocoa/tab_contents_controller.mm
+++ b/chrome/browser/cocoa/tab_contents_controller.mm
@@ -202,6 +202,28 @@ class LocationBarBridge : public LocationBar {
   [starButton_ setImage:[NSImage imageNamed:starImageName]];
 }
 
+// Return the rect, in WebKit coordinates (flipped), of the window's grow box
+// in the coordinate system of the content area of this tab.
+// |windowGrowBox| needs to be in the window's coordinate system.
+- (NSRect)growBoxFromWindowGrowBox:(NSRect)windowGrowBox {
+  NSRect localGrowBox = NSMakeRect(0, 0, 0, 0);
+  NSView* contentView = contents_->GetNativeView();
+  if (contentView) {
+    localGrowBox = windowGrowBox;
+    // The scrollbar assumes that the resizer goes all the way down to the
+    // bottom corner, so we ignore any y offset to the rect itself and use the
+    // entire bottom corner.
+    localGrowBox.origin.y = 0;
+    // Convert to view coordinates from window coordinates.
+    localGrowBox = [contentView convertRect:localGrowBox fromView:nil];
+    // Flip the rect in view coordinates
+    localGrowBox.origin.y = 
+        [contentView frame].size.height - localGrowBox.origin.y - 
+            localGrowBox.size.height;
+  }
+  return localGrowBox;
+}
+
 @end
 
 //--------------------------------------------------------------------------
diff --git a/chrome/browser/cocoa/tab_strip_controller.h b/chrome/browser/cocoa/tab_strip_controller.h
index 2f1bcbf..6062d70 100644
--- a/chrome/browser/cocoa/tab_strip_controller.h
+++ b/chrome/browser/cocoa/tab_strip_controller.h
@@ -57,6 +57,11 @@ class TabContents;
 // Sets whether or not the current page in the frontmost tab is bookmarked.
 - (void)setStarredState:(BOOL)isStarred;
 
+// Return the rect, in WebKit coordinates (flipped), of the window's grow box
+// in the coordinate system of the content area of the currently selected tab.
+// |windowGrowBox| needs to be in the window's coordinate system.
+- (NSRect)selectedTabGrowBoxFromWindowGrowBox:(NSRect)windowGrowBox;
+
 @end
 
 #endif  // CHROME_BROWSER_COCOA_TAB_STRIP_CONTROLLER_H_
diff --git a/chrome/browser/cocoa/tab_strip_controller.mm b/chrome/browser/cocoa/tab_strip_controller.mm
index 864ab12..65ad9b0 100644
--- a/chrome/browser/cocoa/tab_strip_controller.mm
+++ b/chrome/browser/cocoa/tab_strip_controller.mm
@@ -334,6 +334,24 @@ class TabStripBridge : public TabStripModelObserver {
   [selectedController setStarredState:isStarred];
 }
 
+// Return the rect, in WebKit coordinates (flipped), of the window's grow box
+// in the coordinate system of the content area of the currently selected tab.
+// |windowGrowBox| needs to be in the window's coordinate system.
+- (NSRect)selectedTabGrowBoxFromWindowGrowBox:(NSRect)windowGrowBox {
+  TabContents* selectedContents = model_->GetSelectedTabContents();
+  if (!selectedContents) {
+    // When the window is initially being constructed, there may be no currently
+    // selected tab, so pick the first one. If there aren't any, just bail with
+    // an empty rect.
+    selectedContents = model_->GetTabContentsAt(0);
+    if (!selectedContents)
+      return NSMakeRect(0, 0, 0, 0);
+  }
+  TabContentsController* selectedController =
+      [self controllerWithContents:selectedContents];
+  return [selectedController growBoxFromWindowGrowBox:windowGrowBox];
+}
+
 @end
 
 //--------------------------------------------------------------------------
diff --git a/chrome/renderer/render_widget.cc b/chrome/renderer/render_widget.cc
index 7d23d36..04f16f1 100644
--- a/chrome/renderer/render_widget.cc
+++ b/chrome/renderer/render_widget.cc
@@ -703,7 +703,12 @@ void RenderWidget::GetRootWindowResizerRect(WebWidget* webwidget,
   // This is disabled to verify if WebKit is responsible for the slow down
   // that was witnessed in the page cycler tests when the resize corner 
   // code was commited...
+#if defined(OS_MACOSX)
+  // ...we need it enabled on Mac so scrollbars are usable.
+  *rect = resizer_rect_;
+#elif defined(OS_WIN) || defined(OS_LINUX)
   *rect = gfx::Rect();  // resizer_rect_;
+#endif
 }
 
 void RenderWidget::OnImeSetInputMode(bool is_active) {