mac: Move more 10.7 api stuff into sdk_forward_declarations.h

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
index 4b74c36900368f91c59eb5ad5152f8a183731234..a2d4013723d2cbb5ee7a021329348984b7006560 100644
--- a/base/mac/sdk_forward_declarations.h
+++ b/base/mac/sdk_forward_declarations.h
@@ -4,10 +4,15 @@
 
 // This file contains forward declarations for items in later SDKs than the
 // default one with which Chromium is built (currently 10.6).
+// If you call any function from this header, be sure to check at runtime for
+// respondsToSelector: before calling these functions (else your code will crash
+// on older OS X versions that chrome still supports).
 
 #ifndef BASE_MAC_SDK_FORWARD_DECLARATIONS_H_
 #define BASE_MAC_SDK_FORWARD_DECLARATIONS_H_
 
+#import <AppKit/AppKit.h>
+
 #if !defined(MAC_OS_X_VERSION_10_7) || \
     MAC_OS_X_VERSION_MAX_ALLOWED < MAC_OS_X_VERSION_10_7
 enum {
@@ -49,6 +54,14 @@ typedef NSUInteger NSEventSwipeTrackingOptions;
 - (void)setContentsScale:(CGFloat)contentsScale;
 @end
 
+@interface NSScreen (LionSDK)
+- (CGFloat)backingScaleFactor;
+- (NSRect)convertRectToBacking:(NSRect)aRect;
+@end
+
+@interface NSWindow (LionSDK)
+- (CGFloat)backingScaleFactor;
+@end
 #endif  // MAC_OS_X_VERSION_10_7
 
 #endif  // BASE_MAC_SDK_FORWARD_DECLARATIONS_H_