[Mac] (More) RTL support for tab strip

chrome/browser/ui/cocoa/tabs/tab_strip_controller.mm

Index: chrome/browser/ui/cocoa/tabs/tab_strip_controller.mm
diff --git a/chrome/browser/ui/cocoa/tabs/tab_strip_controller.mm b/chrome/browser/ui/cocoa/tabs/tab_strip_controller.mm
index 97eb5f57a8c69e4dc60dc633054ae5fa214548fe..a8499d1c31d7899bdb40c222f624d63d1dd27927 100644
--- a/chrome/browser/ui/cocoa/tabs/tab_strip_controller.mm
+++ b/chrome/browser/ui/cocoa/tabs/tab_strip_controller.mm
@@ -142,6 +142,11 @@ CGFloat FlipXInView(NSView* view, CGFloat width, CGFloat x) {
   return x;
 }
 
+NSRect FlipRectInView(NSView* view, NSRect rect) {
+  rect.origin.x = FlipXInView(view, NSWidth(rect), NSMinX(rect));
+  return rect;
+}
+
 }  // namespace
 
 @interface NSView (PrivateAPI)
@@ -401,8 +406,8 @@ CGFloat FlipXInView(NSView* view, CGFloat width, CGFloat x) {
 
 @implementation TabStripController
 
-@synthesize leftIndentForControls = leftIndentForControls_;
-@synthesize rightIndentForControls = rightIndentForControls_;
+@synthesize leadingIndentForControls = leadingIndentForControls_;
+@synthesize trailingIndentForControls = trailingIndentForControls_;
 
 - (id)initWithView:(TabStripView*)view
         switchView:(NSView*)switchView
@@ -432,8 +437,9 @@ CGFloat FlipXInView(NSView* view, CGFloat width, CGFloat x) {
     defaultFavicon_.reset(
         rb.GetNativeImageNamed(IDR_DEFAULT_FAVICON).CopyNSImage());
 
-    [self setLeftIndentForControls:[[self class] defaultLeftIndentForControls]];
-    [self setRightIndentForControls:0];
+    [self setLeadingIndentForControls:[[self class]
+                                          defaultLeadingIndentForControls]];
+    [self setTrailingIndentForControls:0];
 
     // Add this invisible view first so that it is ordered below other views.
     dragBlockingView_.reset(
@@ -569,7 +575,7 @@ CGFloat FlipXInView(NSView* view, CGFloat width, CGFloat x) {
   return [TabController defaultTabHeight];
 }
 
-+ (CGFloat)defaultLeftIndentForControls {
++ (CGFloat)defaultLeadingIndentForControls {
   // Default indentation leaves enough room so tabs don't overlap with the
   // window controls.
   return 70.0;
@@ -823,14 +829,20 @@ CGFloat FlipXInView(NSView* view, CGFloat width, CGFloat x) {
         availableResizeWidth_ = kUseFullAvailableWidth;
       } else {
         NSView* penultimateTab = [self viewAtIndex:numberOfOpenTabs - 2];
-        availableResizeWidth_ = NSMaxX([penultimateTab frame]);
+        availableResizeWidth_ =
+            cocoa_l10n_util::ShouldDoExperimentalRTLLayout()
+                ? FlipXInView(tabStripView_, 0, NSMinX([penultimateTab frame]))
+                : NSMaxX([penultimateTab frame]);
       }
     } else {
-      // If the rightmost tab is closed, change the available width so that
+      // If the trailing 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).
       NSView* lastTab = [self viewAtIndex:numberOfOpenTabs - 1];
-      availableResizeWidth_ = NSMaxX([lastTab frame]);
+      availableResizeWidth_ =
+          cocoa_l10n_util::ShouldDoExperimentalRTLLayout()
+              ? FlipXInView(tabStripView_, 0, NSMinX([lastTab frame]))
+              : NSMaxX([lastTab frame]);
     }
     tabStripModel_->CloseWebContentsAt(
         index,
@@ -886,12 +898,20 @@ CGFloat FlipXInView(NSView* view, CGFloat width, CGFloat x) {
 
 - (BOOL)isTabFullyVisible:(TabView*)tab {
   NSRect frame = [tab frame];
-  return NSMinX(frame) >= [self leftIndentForControls] &&
-      NSMaxX(frame) <= [self tabAreaRightEdge];
+  if (cocoa_l10n_util::ShouldDoExperimentalRTLLayout()) {
+    return NSMinX(frame) >= [self trailingIndentForControls] &&
+           NSMaxX(frame) <= [self tabAreaRightEdge];
+  } else {
+    return NSMinX(frame) >= [self leadingIndentForControls] &&
+           NSMaxX(frame) <= [self tabAreaRightEdge];
+  }
 }
 
 - (CGFloat)tabAreaRightEdge {
-  return NSMaxX([tabStripView_ frame]) - [self rightIndentForControls];
+  CGFloat rightEdge = cocoa_l10n_util::ShouldDoExperimentalRTLLayout()
+                          ? [self leadingIndentForControls]
+                          : [self trailingIndentForControls];
+  return NSMaxX([tabStripView_ frame]) - rightEdge;
 }
 
 - (void)showNewTabButton:(BOOL)show {
@@ -939,15 +959,15 @@ CGFloat FlipXInView(NSView* view, CGFloat width, CGFloat x) {
     // Account for the width of the new tab button.
     availableSpace -=
         NSWidth([newTabButton_ frame]) + kNewTabButtonOffset - kTabOverlap;
-    // Account for the right-side controls if not in rapid closure mode.
+    // Account for the trailing controls if not in rapid closure mode.
     // (In rapid closure mode, the available width is set based on the
-    // position of the rightmost tab, not based on the width of the tab strip,
-    // so the right controls have already been accounted for.)
-    availableSpace -= [self rightIndentForControls];
+    // position of the trailing tab, not based on the width of the tab strip,
+    // so the trailing controls have already been accounted for.)
+    availableSpace -= [self trailingIndentForControls];
   }
 
-  // Need to leave room for the left-side controls even in rapid closure mode.
-  availableSpace -= [self leftIndentForControls];
+  // Need to leave room for the leading controls even in rapid closure mode.
+  availableSpace -= [self leadingIndentForControls];
 
   // This may be negative, but that's okay (taken care of by |MAX()| when
   // calculating tab sizes). "pinned" tabs in horizontal mode just get a special
@@ -1006,16 +1026,15 @@ CGFloat FlipXInView(NSView* view, CGFloat width, CGFloat x) {
 
   BOOL visible = [[tabStripView_ window] isVisible];
 
-  CGFloat offset =
-      cocoa_l10n_util::ShouldDoExperimentalRTLLayout()
-          ? [self rightIndentForControls]
-          : [self leftIndentForControls];
+  CGFloat offset = [self leadingIndentForControls];
   bool hasPlaceholderGap = false;
   // Whether or not the last tab processed by the loop was a pinned tab.
   BOOL isLastTabPinned = NO;
   CGFloat tabWidthAccumulatedFraction = 0;
   NSInteger laidOutNonPinnedTabs = 0;
 
+  // Lay everything out as if it was LTR and flip at the end
+  // for RTL, if necessary.
   for (TabController* tab in tabArray_.get()) {
     // Ignore a tab that is going through a close animation.
     if ([closingControllers_ containsObject:tab])
@@ -1050,10 +1069,17 @@ CGFloat FlipXInView(NSView* view, CGFloat width, CGFloat x) {
     }
 
     if (placeholderTab_ && !hasPlaceholderGap) {
-      const CGFloat placeholderMin = NSMinX(placeholderFrame_);
-      // If the left edge is to the left of the placeholder's left, but the
-      // mid is to the right of it slide over to make space for it.
-      if (NSMidX(tabFrame) > placeholderMin) {
+      // If the back edge is behind the placeholder's back edge, but the
+      // mid is in front of it of it, slide over to make space for it.
+      bool shouldLeaveGap;
+      if (cocoa_l10n_util::ShouldDoExperimentalRTLLayout()) {
+        const CGFloat tabMidpoint =
+            NSMidX(FlipRectInView(tabStripView_, tabFrame));
+        shouldLeaveGap = tabMidpoint < NSMaxX(placeholderFrame_);
+      } else {
+        shouldLeaveGap = NSMidX(tabFrame) > NSMinX(placeholderFrame_);
+      }
+      if (shouldLeaveGap) {
         hasPlaceholderGap = true;
         offset += NSWidth(placeholderFrame_);
         offset -= kTabOverlap;
@@ -2019,6 +2045,7 @@ CGFloat FlipXInView(NSView* view, CGFloat width, CGFloat x) {
 
   DCHECK(index && disposition);
   NSInteger i = 0;
+  BOOL isRTL = cocoa_l10n_util::ShouldDoExperimentalRTLLayout();
   for (TabController* tab in tabArray_.get()) {
     NSView* view = [tab view];
     DCHECK([view isKindOfClass:[TabView class]]);
@@ -2034,16 +2061,18 @@ CGFloat FlipXInView(NSView* view, CGFloat width, CGFloat x) {
     if (frame.size.width < 1.0)
       frame.size.width = 1.0;  // try to avoid complete failure
 
-    // Drop in a new tab to the left of tab |i|?
-    if (point.x < (frame.origin.x + kLRProportion * frame.size.width)) {
+    CGFloat rightEdge = NSMaxX(frame) - kLRProportion * frame.size.width;
+    CGFloat leftEdge = frame.origin.x + kLRProportion * frame.size.width;
+
+    // Drop in a new tab before  tab |i|?
+    if (isRTL ? point.x > rightEdge : point.x < leftEdge) {
       *index = i;
       *disposition = WindowOpenDisposition::NEW_FOREGROUND_TAB;
       return;
     }
 
     // Drop on tab |i|?
-    if (point.x <= (frame.origin.x +
-                       (1.0 - kLRProportion) * frame.size.width)) {
+    if (isRTL ? point.x >= leftEdge : point.x <= rightEdge) {
       *index = i;
       *disposition = WindowOpenDisposition::CURRENT_TAB;
       return;
@@ -2220,20 +2249,26 @@ CGFloat FlipXInView(NSView* view, CGFloat width, CGFloat x) {
 }
 
 - (void)addCustomWindowControls {
+  BOOL isRTL = cocoa_l10n_util::ShouldDoExperimentalRTLLayout();
   if (!customWindowControls_) {
     // Make the container view.
     CGFloat height = NSHeight([tabStripView_ frame]);
-    NSRect frame = NSMakeRect(0, 0, [self leftIndentForControls], height);
+    CGFloat width = [self leadingIndentForControls];
+    CGFloat xOrigin = isRTL ? NSWidth([tabStripView_ frame]) - width : 0;
+    NSRect frame = NSMakeRect(xOrigin, 0, width, height);
     customWindowControls_.reset(
         [[CustomWindowControlsView alloc] initWithFrame:frame]);
     [customWindowControls_
-        setAutoresizingMask:NSViewMaxXMargin | NSViewHeightSizable];
+        setAutoresizingMask:isRTL ? NSViewMaxXMargin | NSViewHeightSizable
+                                  : NSViewMinXMargin | NSViewHeightSizable];
 
     // Add the traffic light buttons. The horizontal layout was determined by
     // manual inspection on Yosemite.
     CGFloat closeButtonX = 11;
     CGFloat pinnedButtonX = 31;
     CGFloat zoomButtonX = 51;
+    if (isRTL)
+      std::swap(closeButtonX, zoomButtonX);
 
     NSUInteger styleMask = [[tabStripView_ window] styleMask];
     NSButton* closeButton = [NSWindow standardWindowButton:NSWindowCloseButton
@@ -2265,7 +2300,13 @@ CGFloat FlipXInView(NSView* view, CGFloat width, CGFloat x) {
     [customWindowControls_
         addTrackingArea:customWindowControlsTrackingArea_.get()];
   }
-
+  if (isRTL &&
+      NSMaxX([customWindowControls_ frame]) != NSMaxX([tabStripView_ frame])) {
+    NSRect frame = [customWindowControls_ frame];
+    frame.origin.x =
+        NSMaxX([tabStripView_ frame]) - [self leadingIndentForControls];
+    [customWindowControls_ setFrame:frame];
+  }
   if (![permanentSubviews_ containsObject:customWindowControls_]) {
     [self addSubviewToPermanentList:customWindowControls_];
     [self regenerateSubviewList];