Prepare ui/ module for compilation with OS X 10.7 deployment target.

ui/base/cocoa/base_view.mm

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ui/base/cocoa/base_view.h"
 
 #include "base/mac/mac_util.h"
 
 NSString* kViewDidBecomeFirstResponder =
     @"Chromium.kViewDidBecomeFirstResponder";
@@ skipping 152 matching lines @@
 - (void)keyDown:(NSEvent*)theEvent {
   if ([self keyEvent:theEvent] != kEventHandled)
     [super keyDown:theEvent];
 }
 
 - (void)keyUp:(NSEvent*)theEvent {
   if ([self keyEvent:theEvent] != kEventHandled)
     [super keyUp:theEvent];
 }
 
-- (void)pressureChangeWithEvent:(NSEvent*)theEvent {
-  NSInteger newStage = [theEvent stage];
-  if (pressureEventStage_ == newStage)
-    return;
-
-  // Call the force touch event when the stage reaches 2, which is the value
-  // for force touch.
-  if (newStage == 2) {
-    [self forceTouchEvent:theEvent];

[Avi (use Gerrit), 2016/03/08 20:07:54]

I'm rather uncomfortable here. While it seems like no one is calling
-pressureChangeWithEvent:, this call to -forceTouchEvent: seems to be overridden
in RenderWidgetHostViewMac (see
https://code.google.com/p/chromium/codesearch#search/&q=forceTouchEvent ).
Either this should somehow be hooked in, or the other code should be removed.

[Avi (use Gerrit), 2016/03/08 20:13:08]

OK, I'm really unsure about this. -pressureChangeWithEvent: seems to be the hook
for Force Touch (see
http://www.metaltoad.com/blog/use-the-force-touch-mac-programming ,
https://gregheo.com/blog/force-touch/ , and
https://webkit.googlesource.com/WebKit/+/dc0d9c76834640b3f2c9a180cf2e1ff5e8aa...
).

[erikchen, 2016/03/08 20:57:41]

Whoops! Good catch. 

-  }
-  pressureEventStage_ = newStage;

[Avi (use Gerrit), 2016/03/08 20:07:54]

pressureEventStage_ is only used in this method; if we remove this method remove
the variable from the class definition in the .h file.

-}
-
 - (void)flagsChanged:(NSEvent*)theEvent {
   if ([self keyEvent:theEvent] != kEventHandled)
     [super flagsChanged:theEvent];
 }
 
 - (gfx::Rect)flipNSRectToRect:(NSRect)rect {
   gfx::Rect new_rect(NSRectToCGRect(rect));
   new_rect.set_y(NSHeight([self bounds]) - new_rect.bottom());
   return new_rect;
 }
 
 - (NSRect)flipRectToNSRect:(gfx::Rect)rect {
   NSRect new_rect(NSRectFromCGRect(rect.ToCGRect()));
   new_rect.origin.y = NSHeight([self bounds]) - NSMaxY(new_rect);
   return new_rect;
 }
 
 @end