[Mac]Implement ViewID support.

chrome/browser/cocoa/reload_button.mm

Index: chrome/browser/cocoa/reload_button.mm
diff --git a/chrome/browser/cocoa/reload_button.mm b/chrome/browser/cocoa/reload_button.mm
index 53e6c58239638eba4928223cb6795ee039e5a6f4..e5a335729d8e48e920b007e477000f9b80bd9931 100644
--- a/chrome/browser/cocoa/reload_button.mm
+++ b/chrome/browser/cocoa/reload_button.mm
@@ -6,6 +6,7 @@
 
 #include "base/nsimage_cache_mac.h"
 #include "chrome/app/chrome_dll_resource.h"
+#import "chrome/browser/cocoa/view_id_util.h"
 
 namespace {
 
@@ -50,6 +51,7 @@ NSString* const kStopImageName = @"stop_Template.pdf";
   // Don't allow multi-clicks, because the user probably wouldn't ever
   // want to stop+reload or reload+stop.
   [self setIgnoresMultiClick:YES];
+  [self setCommand:IDC_RELOAD];
 }
 
 - (void)setIsLoading:(BOOL)isLoading force:(BOOL)force {
@@ -60,17 +62,17 @@ NSString* const kStopImageName = @"stop_Template.pdf";
   // that reload mode is desired and make no change.
   if (isLoading) {
     [self setImage:nsimage_cache::ImageNamed(kStopImageName)];
-    [self setTag:IDC_STOP];
+    [self setCommand:IDC_STOP];
   } else if (force || ![self isMouseInside]) {
     [self setImage:nsimage_cache::ImageNamed(kReloadImageName)];
-    [self setTag:IDC_RELOAD];
-  } else if ([self tag] == IDC_STOP) {
+    [self setCommand:IDC_RELOAD];
+  } else if ([self command] == IDC_STOP) {
     pendingReloadMode_ = YES;
   }
 }
 
 - (BOOL)sendAction:(SEL)theAction to:(id)theTarget {
-  if ([self tag] == IDC_STOP) {
+  if ([self command] == IDC_STOP) {
     // The stop command won't be valid after the attempt to change
     // back to reload.  But it "worked", so short-circuit it.
     const BOOL ret =
@@ -105,6 +107,11 @@ NSString* const kStopImageName = @"stop_Template.pdf";
   return trackingArea_ && isMouseInside_;
 }
 
+// Tag is used solely for ViewID. Override to prevent changing of it.
+- (NSInteger)tag {
+  return view_id_util::ViewIDToTag(VIEW_ID_RELOAD_BUTTON);
+}
+
 @end  // ReloadButton
 
 @implementation ReloadButton (Testing)