[Mac] Move the large block of NSEvent forward declarations to a shared header.

chrome/browser/renderer_host/chrome_render_widget_host_view_mac_delegate.mm

Index: chrome/browser/renderer_host/chrome_render_widget_host_view_mac_delegate.mm
diff --git a/chrome/browser/renderer_host/chrome_render_widget_host_view_mac_delegate.mm b/chrome/browser/renderer_host/chrome_render_widget_host_view_mac_delegate.mm
index f8e01953fb55405a6115b161afc770e15370ad28..17dac1bc613953e2cb4025c1aaf4e1b70011a141 100644
--- a/chrome/browser/renderer_host/chrome_render_widget_host_view_mac_delegate.mm
+++ b/chrome/browser/renderer_host/chrome_render_widget_host_view_mac_delegate.mm
@@ -6,6 +6,7 @@
 
 #include <cmath>
 
+#import "base/mac/sdk_forward_declarations.h"
 #include "base/prefs/pref_service.h"
 #include "base/strings/sys_string_conversions.h"
 #include "chrome/browser/devtools/devtools_window.h"
@@ -30,41 +31,6 @@
 
 using content::RenderViewHost;
 
-// Declare things that are part of the 10.7 SDK.
-#if !defined(MAC_OS_X_VERSION_10_7) || \
-    MAC_OS_X_VERSION_MAX_ALLOWED < MAC_OS_X_VERSION_10_7
-enum {
-  NSEventPhaseNone        = 0, // event not associated with a phase.
-  NSEventPhaseBegan       = 0x1 << 0,
-  NSEventPhaseStationary  = 0x1 << 1,
-  NSEventPhaseChanged     = 0x1 << 2,
-  NSEventPhaseEnded       = 0x1 << 3,
-  NSEventPhaseCancelled   = 0x1 << 4,
-};
-typedef NSUInteger NSEventPhase;
-
-enum {
-  NSEventSwipeTrackingLockDirection = 0x1 << 0,
-  NSEventSwipeTrackingClampGestureAmount = 0x1 << 1
-};
-typedef NSUInteger NSEventSwipeTrackingOptions;
-
-@interface NSEvent (LionAPI)
-+ (BOOL)isSwipeTrackingFromScrollEventsEnabled;
-
-- (NSEventPhase)phase;
-- (CGFloat)scrollingDeltaX;
-- (CGFloat)scrollingDeltaY;
-- (void)trackSwipeEventWithOptions:(NSEventSwipeTrackingOptions)options
-          dampenAmountThresholdMin:(CGFloat)minDampenThreshold
-                               max:(CGFloat)maxDampenThreshold
-                      usingHandler:(void (^)(CGFloat gestureAmount,
-                                             NSEventPhase phase,
-                                             BOOL isComplete,
-                                             BOOL *stop))trackingHandler;
-@end
-#endif  // 10.7
-
 @interface ChromeRenderWidgetHostViewMacDelegate ()
 - (BOOL)maybeHandleHistorySwiping:(NSEvent*)theEvent;
 - (void)spellCheckEnabled:(BOOL)enabled checked:(BOOL)checked;