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

base/mac/sdk_forward_declarations.h

Index: base/mac/sdk_forward_declarations.h
diff --git a/base/mac/sdk_forward_declarations.h b/base/mac/sdk_forward_declarations.h
new file mode 100644
index 0000000000000000000000000000000000000000..387400d43de55c53e746bf513f0d29a334e7a348
--- /dev/null
+++ b/base/mac/sdk_forward_declarations.h
@@ -0,0 +1,48 @@
+// Copyright (c) 2012 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.
+
+// This file contains forward declarations for items in later SDKs than the
+// default one with which Chromium is built (currently 10.6).
+
+#ifndef BASE_MAC_SDK_FORWARD_DECLARATIONS_H_
+#define BASE_MAC_SDK_FORWARD_DECLARATIONS_H_
+
+#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 (LionSDK)
++ (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;
+
+- (BOOL)isDirectionInvertedFromDevice;
+
+@end
+#endif  // MAC_OS_X_VERSION_10_7
+
+#endif  // BASE_MAC_SDK_FORWARD_DECLARATIONS_H_