Add ScopedObjCClassSwizzler in base/mac, absorbs objc_method_swizzle and ScopedClassSwizzler

ScopedClassSwizzler from ui/test is wanted for new tests where it can't
currently be accessed. It also re-implements a concept in
chrome/common/mac/objc_method_swizzle.*

This change adds base::mac::ScopedObjCClassSwizzler, merges concepts
from objc_method_swizzle, and adjusts chrome_browser_application_mac.mm
to use the new swizzler.

The test from objc_method_swizzle is adapted and extended for the scoped
swizzler.

BUG=378134
TEST=base_unittests

Review URL: https://codereview.chromium.org/345243007

Cr-Commit-Position: refs/heads/master@{#288943}
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@288943 0039d316-1c4b-4281-b951-d872f2087c98

5 files changed, 12 insertions, 42 deletions

diff --git a/ui/base/cocoa/cocoa_base_utils_unittest.mm b/ui/base/cocoa/cocoa_base_utils_unittest.mm
index 5749e2d..f379120 100644
--- a/ui/base/cocoa/cocoa_base_utils_unittest.mm
+++ b/ui/base/cocoa/cocoa_base_utils_unittest.mm
@@ -6,6 +6,7 @@
 
 #import <objc/objc-class.h>
 
+#import "base/mac/scoped_objc_class_swizzler.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "testing/platform_test.h"
 #include "ui/events/event_constants.h"
@@ -39,8 +40,8 @@ TEST_F(CocoaBaseUtilsTest, WindowOpenDispositionFromNSEvent) {
 
   // Shift+Middle Click = new foreground tab.
   {
-    ScopedClassSwizzler swizzler([NSEvent class], [TestEvent class],
-                                 @selector(modifierFlags));
+    base::mac::ScopedObjCClassSwizzler swizzler(
+        [NSEvent class], [TestEvent class], @selector(modifierFlags));
     me = cocoa_test_event_utils::MouseEventWithType(NSOtherMouseUp,
                                                     NSShiftKeyMask);
     EXPECT_EQ(NEW_FOREGROUND_TAB, WindowOpenDispositionFromNSEvent(me));
diff --git a/ui/events/cocoa/events_mac_unittest.mm b/ui/events/cocoa/events_mac_unittest.mm
index 77f8549..f58cfd0 100644
--- a/ui/events/cocoa/events_mac_unittest.mm
+++ b/ui/events/cocoa/events_mac_unittest.mm
@@ -7,6 +7,7 @@
 #import <Cocoa/Cocoa.h>
 
 #include "base/mac/scoped_cftyperef.h"
+#import "base/mac/scoped_objc_class_swizzler.h"
 #include "base/memory/scoped_ptr.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "ui/events/event_constants.h"
@@ -32,7 +33,7 @@ NSWindow* g_test_window = nil;
 @end
 
 @implementation MiddleMouseButtonNumberDonor
-- (NSUInteger)buttonNumber { return 2; }
+- (NSInteger)buttonNumber { return 2; }
 @end
 
 @implementation TestWindowDonor
@@ -57,7 +58,7 @@ class EventsMacTest : public CocoaTest {
 
   void SwizzleMiddleMouseButton() {
     DCHECK(!swizzler_);
-    swizzler_.reset(new ScopedClassSwizzler(
+    swizzler_.reset(new base::mac::ScopedObjCClassSwizzler(
         [NSEvent class],
         [MiddleMouseButtonNumberDonor class],
         @selector(buttonNumber)));
@@ -67,10 +68,8 @@ class EventsMacTest : public CocoaTest {
     DCHECK(!g_test_window);
     DCHECK(!swizzler_);
     g_test_window = test_window();
-    swizzler_.reset(new ScopedClassSwizzler(
-        [NSEvent class],
-        [TestWindowDonor class],
-        @selector(window)));
+    swizzler_.reset(new base::mac::ScopedObjCClassSwizzler(
+        [NSEvent class], [TestWindowDonor class], @selector(window)));
   }
 
   void ClearSwizzle() {
@@ -117,7 +116,7 @@ class EventsMacTest : public CocoaTest {
   }
 
  private:
-  scoped_ptr<ScopedClassSwizzler> swizzler_;
+  scoped_ptr<base::mac::ScopedObjCClassSwizzler> swizzler_;
 
   DISALLOW_COPY_AND_ASSIGN(EventsMacTest);
 };
diff --git a/ui/events/test/cocoa_test_event_utils.h b/ui/events/test/cocoa_test_event_utils.h
index 6c4994d..76c6a32 100644
--- a/ui/events/test/cocoa_test_event_utils.h
+++ b/ui/events/test/cocoa_test_event_utils.h
@@ -11,20 +11,6 @@
 
 #include "base/basictypes.h"
 
-// Within a given scope, replace the selector |selector| on |target| with that
-// from |source|.
-class ScopedClassSwizzler {
- public:
-  ScopedClassSwizzler(Class target, Class source, SEL selector);
-  ~ScopedClassSwizzler();
-
- private:
-  Method old_selector_impl_;
-  Method new_selector_impl_;
-
-  DISALLOW_COPY_AND_ASSIGN(ScopedClassSwizzler);
-};
-
 namespace cocoa_test_event_utils {
 
 // Create synthetic mouse events for testing. Currently these are very
diff --git a/ui/events/test/cocoa_test_event_utils.mm b/ui/events/test/cocoa_test_event_utils.mm
index 4f0cb67..2694b84e 100644
--- a/ui/events/test/cocoa_test_event_utils.mm
+++ b/ui/events/test/cocoa_test_event_utils.mm
@@ -6,22 +6,6 @@
 
 #include "ui/events/test/cocoa_test_event_utils.h"
 
-ScopedClassSwizzler::ScopedClassSwizzler(Class target, Class source,
-                                         SEL selector) {
-  old_selector_impl_ = class_getInstanceMethod(target, selector);
-  new_selector_impl_ = class_getInstanceMethod(source, selector);
-  if (!old_selector_impl_ && !new_selector_impl_) {
-    // Try class methods.
-    old_selector_impl_ = class_getClassMethod(target, selector);
-    new_selector_impl_ = class_getClassMethod(source, selector);
-  }
-  method_exchangeImplementations(old_selector_impl_, new_selector_impl_);
-}
-
-ScopedClassSwizzler::~ScopedClassSwizzler() {
-  method_exchangeImplementations(old_selector_impl_, new_selector_impl_);
-}
-
 namespace cocoa_test_event_utils {
 
 NSEvent* MouseEventAtPoint(NSPoint point, NSEventType type,
diff --git a/ui/views/test/event_generator_delegate_mac.mm b/ui/views/test/event_generator_delegate_mac.mm
index d0e351a..db94d34 100644
--- a/ui/views/test/event_generator_delegate_mac.mm
+++ b/ui/views/test/event_generator_delegate_mac.mm
@@ -4,13 +4,13 @@
 
 #import <Cocoa/Cocoa.h>
 
+#import "base/mac/scoped_objc_class_swizzler.h"
 #include "base/memory/singleton.h"
 #include "ui/events/event_processor.h"
 #include "ui/events/event_target.h"
 #include "ui/events/event_target_iterator.h"
 #include "ui/events/event_targeter.h"
 #include "ui/events/test/event_generator.h"
-#import "ui/events/test/cocoa_test_event_utils.h"
 #include "ui/gfx/mac/coordinate_conversion.h"
 
 namespace {
@@ -293,7 +293,7 @@ class EventGeneratorDelegateMac : public ui::EventTarget,
 
   ui::test::EventGenerator* owner_;
   NSWindow* window_;
-  scoped_ptr<ScopedClassSwizzler> swizzle_pressed_;
+  scoped_ptr<base::mac::ScopedObjCClassSwizzler> swizzle_pressed_;
 
   DISALLOW_COPY_AND_ASSIGN(EventGeneratorDelegateMac);
 };
@@ -332,7 +332,7 @@ void EventGeneratorDelegateMac::SetContext(ui::test::EventGenerator* owner,
   owner_ = owner;
   window_ = window;
   if (owner_) {
-    swizzle_pressed_.reset(new ScopedClassSwizzler(
+    swizzle_pressed_.reset(new base::mac::ScopedObjCClassSwizzler(
         [NSEvent class],
         [NSEventDonor class],
         @selector(pressedMouseButtons)));