Send Chrome's process id to the app shim.

chrome/common/mac/app_mode_common.h

Index: chrome/common/mac/app_mode_common.h
diff --git a/chrome/common/mac/app_mode_common.h b/chrome/common/mac/app_mode_common.h
index d397c4b3c590aee399052bda51b761b9afa8d66e..684a5a210f28c9a5123a11869750dd8e78beda4d 100644
--- a/chrome/common/mac/app_mode_common.h
+++ b/chrome/common/mac/app_mode_common.h
@@ -15,6 +15,9 @@
 
 namespace app_mode {
 
+// The process ID of the Chrome process that launched the app shim.
+extern const char kChromeProcessId[];
+
 // These are keys for an Apple Event ping that the app shim process sends to
 // Chrome to get confirmation that Chrome is alive. The main Chrome process
 // doesn't need to register any handlers for them -- the event is just sent for