Add a histogram for tracking web store promo

chrome/common/extensions/extension_constants.h

Index: chrome/common/extensions/extension_constants.h
diff --git a/chrome/common/extensions/extension_constants.h b/chrome/common/extensions/extension_constants.h
index 332f386d5eb8901c21932c156a0fc9a49baca836..3e474f7082ec58a8ecae4dc7ce95adc3932e0d2a 100644
--- a/chrome/common/extensions/extension_constants.h
+++ b/chrome/common/extensions/extension_constants.h
@@ -224,6 +224,9 @@ namespace extension_misc {
   // The extension id of the Web Store component application.
   extern const char* kWebStoreAppId;
 
+  // Web Store app id used in the new tab page.

[Erik does not do reviews, 2010/11/10 23:29:51]

I don't get it.  How can we have two different app ids for the same app?  This
seems like it would break some important stuff.

+  extern const char* kNTPWebStoreAppId;
+
   // Note: this structure is an ASN.1 which encodes the algorithm used
   // with its parameters. This is defined in PKCS #1 v2.1 (RFC 3447).
   // It is encoding: { OID sha1WithRSAEncryption      PARAMETERS NULL }
@@ -239,6 +242,15 @@ namespace extension_misc {
     LAUNCH_PANEL,
     LAUNCH_TAB
   };
+
+  // These are the buckets used in the apps promo histogram.
+  enum AppsPromoBuckets {
+    LAUNCH_APP,
+    LAUNCH_WEB_STORE,
+    CLOSE_PROMO,
+    EXPIRE_PROMO,
+    MAX = EXPIRE_PROMO

[Erik does not do reviews, 2010/11/10 23:29:51]

this is wrong.  From histogram.h: "the samples should always be less than
boundary_value".

+  };
 }  // extension_misc
 
 #endif  // CHROME_COMMON_EXTENSIONS_EXTENSION_CONSTANTS_H_