P2.1a.

chrome/browser/cocoa/tab_strip_controller.mm

Index: chrome/browser/cocoa/tab_strip_controller.mm
diff --git a/chrome/browser/cocoa/tab_strip_controller.mm b/chrome/browser/cocoa/tab_strip_controller.mm
index 029bdb7ee90a18afdd6435eb463cb4d70c068c04..46834b24d96445dd05cd9b3a0f69d440771183ec 100644
--- a/chrome/browser/cocoa/tab_strip_controller.mm
+++ b/chrome/browser/cocoa/tab_strip_controller.mm
@@ -576,16 +576,32 @@ private:
     if (!isClosingLastTab) {
       // Limit the width available for laying out tabs so that tabs are not
       // resized until a later time (when the mouse leaves the tab strip).
-      // TODO(pinkerton): re-visit when handling tab overflow.
-      // http://crbug.com/188
       NSView* penultimateTab = [self viewAtIndex:numberOfOpenTabs - 2];
       availableResizeWidth_ = NSMaxX([penultimateTab frame]);
     } else {
       // If the rightmost tab is closed, change the available width so that
       // another tab's close button lands below the cursor (assuming the tabs
-      // are currently below their maximum width and can grow).
+      // are currently below their maximum width and can grow) if possible.
       NSView* lastTab = [self viewAtIndex:numberOfOpenTabs - 1];
       availableResizeWidth_ = NSMaxX([lastTab frame]);
+
+      // Since close buttons are on the left, this is a bit tricky. To make this
+      // at all possible, the rightmost tab keeps its narrow pre-close width
+      // and the other tabs expand to push it over.
+      // Only do this if the other tabs can be pushed far enough, though.
+      lastClosedTabWidth_.reset();
+      const CGFloat kPinnedTabWidth = [TabController pinnedTabWidth];
+      const CGFloat pinnedWidth =
+          [self numberOfOpenPinnedTabs] * (kPinnedTabWidth - kTabOverlap);
+      const CGFloat kMaxTabWidth = [TabController maxTabWidth];
+      const CGFloat unpinnedWidth =  // 1 tab is candidate for being shorter
+          ([self numberOfOpenUnpinnedTabs] - 1) * (kMaxTabWidth - kTabOverlap);
+      CGFloat candidateWidth = NSWidth([lastTab frame]);
+      // Technically, it should be
+      // |pinnedWidth + unpinnedWidth + widthOfPartOfLastTabThatContainsClose|,
+      // but that's complicated _and_ makes the last tab look very thin.
+      if (pinnedWidth + unpinnedWidth >= availableResizeWidth_)
+        lastClosedTabWidth_.reset(new CGFloat(candidateWidth));
     }
     tabStripModel_->CloseTabContentsAt(index);
   } else {
@@ -667,6 +683,8 @@ private:
   CGFloat availableWidth = 0;
   if ([self inRapidClosureMode]) {
     availableWidth = availableResizeWidth_;
+    if (lastClosedTabWidth_.get())
+      availableWidth -= *lastClosedTabWidth_.get();
   } else {
     availableWidth = NSWidth([tabStripView_ frame]);
     availableWidth -= NSWidth([newTabButton_ frame]) + kNewTabButtonOffset;
@@ -681,10 +699,13 @@ private:
   // Initialize |unpinnedTabWidth| in case there aren't any unpinned tabs; this
   // value shouldn't actually be used.
   CGFloat unpinnedTabWidth = kMaxTabWidth;
-  const NSInteger numberOfOpenUnpinnedTabs = [self numberOfOpenUnpinnedTabs];
+  const NSInteger numberOfOpenUnpinnedTabs = [self numberOfOpenUnpinnedTabs]
+      - (lastClosedTabWidth_.get() ? 1 : 0);
   if (numberOfOpenUnpinnedTabs) {  // Find the width of an unpinned tab.
     // Add in the amount we "get back" from the tabs overlapping.
     availableWidthForUnpinned += (numberOfOpenUnpinnedTabs - 1) * kTabOverlap;
+    if (lastClosedTabWidth_.get())
+      availableWidthForUnpinned += kTabOverlap;
 
     // Divide up the space between the unpinned tabs.
     unpinnedTabWidth = availableWidthForUnpinned / numberOfOpenUnpinnedTabs;
@@ -697,13 +718,14 @@ private:
   BOOL visible = [[tabStripView_ window] isVisible];
 
   CGFloat offset = [self indentForControls];
-  NSUInteger i = 0;
   bool hasPlaceholderGap = false;
+  int openTabCount = 0;
   for (TabController* tab in tabArray_.get()) {
     // Ignore a tab that is going through a close animation.
     if ([closingControllers_ containsObject:tab])
       continue;
 
+    ++openTabCount;
     BOOL isPlaceholder = [[tab view] isEqual:placeholderTab_];
     NSRect tabFrame = [[tab view] frame];
     tabFrame.size.height = [[self class] defaultTabHeight] + 1;
@@ -750,6 +772,12 @@ private:
     if ([tab selected])
       tabFrame.size.width = MAX(tabFrame.size.width, kMinSelectedTabWidth);
 
+    // When in rapid-closure mode, treat the width of the last tab in a way
+    // that its close button ends up below the cursor.
+    BOOL isLastOpenTab = tabStripModel_->count() == openTabCount;
+    if (isLastOpenTab && lastClosedTabWidth_.get())
+      tabFrame.size.width = *lastClosedTabWidth_.get();
+
     // Animate a new tab in by putting it below the horizon unless told to put
     // it in a specific location (i.e., from a drop).
     if (newTab && visible && animate) {
@@ -776,7 +804,6 @@ private:
 
     offset += NSWidth(tabFrame);
     offset -= kTabOverlap;
-    i++;
   }
 
   // Hide the new tab button if we're explicitly told to. It may already
@@ -891,6 +918,7 @@ private:
   // If a tab is being inserted, we can again use the entire tab strip width
   // for layout.
   availableResizeWidth_ = kUseFullAvailableWidth;
+  lastClosedTabWidth_.reset();
 
   // We don't need to call |-layoutTabs| if the tab will be in the foreground
   // because it will get called when the new tab is selected by the tab model.
@@ -1409,6 +1437,7 @@ private:
     mouseInside_ = NO;
     [self setTabTrackingAreasEnabled:NO];
     availableResizeWidth_ = kUseFullAvailableWidth;
+    lastClosedTabWidth_.reset();
     [hoveredTab_ mouseExited:event];
     hoveredTab_ = nil;
     [self layoutTabs];