Start a drag if the tab is dragged off the sides of the window.

BUG=14926
TEST=drag tabs and make sure nothing breaks.
Review URL: http://codereview.chromium.org/195043

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@25787 0039d316-1c4b-4281-b951-d872f2087c98

6 files changed, 36 insertions, 3 deletions

diff --git a/chrome/browser/cocoa/browser_window_controller.mm b/chrome/browser/cocoa/browser_window_controller.mm
index 8971cea..3c7b6e8 100644
--- a/chrome/browser/cocoa/browser_window_controller.mm
+++ b/chrome/browser/cocoa/browser_window_controller.mm
@@ -817,6 +817,10 @@ willPositionSheet:(NSWindow*)sheet
                                  yStretchiness:0];
 }
 
+- (BOOL)isTabFullyVisible:(TabView*)tab {
+  return [tabStripController_ isTabFullyVisible:tab];
+}
+
 - (void)showNewTabButton:(BOOL)show {
   [tabStripController_ showNewTabButton:show];
 }
diff --git a/chrome/browser/cocoa/tab_strip_controller.h b/chrome/browser/cocoa/tab_strip_controller.h
index e1778b5..e9f0625 100644
--- a/chrome/browser/cocoa/tab_strip_controller.h
+++ b/chrome/browser/cocoa/tab_strip_controller.h
@@ -120,6 +120,12 @@ class ToolbarModel;
                           frame:(NSRect)frame
                   yStretchiness:(CGFloat)yStretchiness;
 
+// Returns whether or not |tab| can still be fully seen in the tab strip or if
+// its current position would cause it be obscured by things such as the edge
+// of the window or the window decorations. Returns YES only if the entire tab
+// is visible.
+- (BOOL)isTabFullyVisible:(TabView*)tab;
+
 // Show or hide the new tab button. The button is hidden immediately, but
 // waits until the next call to |-layoutTabs| to show it again.
 - (void)showNewTabButton:(BOOL)show;
diff --git a/chrome/browser/cocoa/tab_strip_controller.mm b/chrome/browser/cocoa/tab_strip_controller.mm
index 2035cdc..0a2c79b 100644
--- a/chrome/browser/cocoa/tab_strip_controller.mm
+++ b/chrome/browser/cocoa/tab_strip_controller.mm
@@ -37,6 +37,10 @@ NSString* const kTabStripNumberOfTabsChanged = @"kTabStripNumberOfTabsChanged";
 // view.
 static const float kUseFullAvailableWidth = -1.0;
 
+// Left-side indent for tab layout so tabs don't overlap with the window
+// controls.
+static const float kIndentLeavingSpaceForControls = 64.0;
+
 // A simple view class that prevents the Window Server from dragging the area
 // behind tabs. Sometimes core animation confuses it. Unfortunately, it can also
 // falsely pick up clicks during rapid tab closure, so we have to account for
@@ -321,6 +325,12 @@ static const float kUseFullAvailableWidth = -1.0;
   [self layoutTabs];
 }
 
+- (BOOL)isTabFullyVisible:(TabView*)tab {
+  NSRect frame = [tab frame];
+  return NSMinX(frame) >= kIndentLeavingSpaceForControls &&
+      NSMaxX(frame) <= NSMaxX([tabView_ frame]);
+}
+
 - (void)showNewTabButton:(BOOL)show {
   forceNewTabButtonHidden_ = show ? NO : YES;
   if (forceNewTabButtonHidden_)
@@ -338,7 +348,6 @@ static const float kUseFullAvailableWidth = -1.0;
 // tabs would cause an overflow.
 - (void)layoutTabsWithAnimation:(BOOL)animate
              regenerateSubviews:(BOOL)doUpdate {
-  const float kIndentLeavingSpaceForControls = 64.0;
   const float kTabOverlap = 20.0;
   const float kNewTabButtonOffset = 8.0;
   const float kMaxTabWidth = [TabController maxTabWidth];
diff --git a/chrome/browser/cocoa/tab_view.mm b/chrome/browser/cocoa/tab_view.mm
index 351882c..a277627 100644
--- a/chrome/browser/cocoa/tab_view.mm
+++ b/chrome/browser/cocoa/tab_view.mm
@@ -267,9 +267,12 @@ static const CGFloat kRapidCloseDist = 2.5;
                                          frame:NSOffsetRect(sourceTabFrame_,
                                                             offset, 0)
                                  yStretchiness:stretchiness];
-
+    // Check that we haven't pulled the tab too far to start a drag. This
+    // can include either pulling it too far down, or off the side of the tab
+    // strip that would cause it to no longer be fully visible.
+    BOOL stillVisible = [sourceController_ isTabFullyVisible:self];
     CGFloat tearForce = fabs(thisPoint.y - dragOrigin_.y);
-    if (tearForce > kTearDistance) {
+    if (tearForce > kTearDistance || !stillVisible) {
       draggingWithinTabStrip_ = NO;
       // When you finally leave the strip, we treat that as the origin.
       dragOrigin_.x = thisPoint.x;
diff --git a/chrome/browser/cocoa/tab_window_controller.h b/chrome/browser/cocoa/tab_window_controller.h
index 4c0f07a..76dfdc4 100644
--- a/chrome/browser/cocoa/tab_window_controller.h
+++ b/chrome/browser/cocoa/tab_window_controller.h
@@ -73,6 +73,12 @@
 // waits until the next call to |-layoutTabs| to show it again.
 - (void)showNewTabButton:(BOOL)show;
 
+// Returns whether or not |tab| can still be fully seen in the tab strip or if
+// its current position would cause it be obscured by things such as the edge
+// of the window or the window decorations. Returns YES only if the entire tab
+// is visible. The default implementation always returns YES.
+- (BOOL)isTabFullyVisible:(TabView*)tab;
+
 // Called to check if the receiver can receive dragged tabs from
 // source.  Return YES if so.  The default implementation returns NO.
 - (BOOL)canReceiveFrom:(TabWindowController*)source;
diff --git a/chrome/browser/cocoa/tab_window_controller.mm b/chrome/browser/cocoa/tab_window_controller.mm
index 7684f13..5e9ce23 100644
--- a/chrome/browser/cocoa/tab_window_controller.mm
+++ b/chrome/browser/cocoa/tab_window_controller.mm
@@ -155,6 +155,11 @@
   [self showNewTabButton:YES];
 }
 
+- (BOOL)isTabFullyVisible:(TabView*)tab {
+  // Subclasses should implement this, but it's not necessary.
+  return YES;
+}
+
 - (void)showNewTabButton:(BOOL)show {
   // subclass must implement
   NOTIMPLEMENTED();