Remove URLs from chrome.tabs.executeScript permission warning.

extensions/common/manifest_constants.cc

Index: extensions/common/manifest_constants.cc
diff --git a/extensions/common/manifest_constants.cc b/extensions/common/manifest_constants.cc
index fe84e8ca1ab1e5f280b854ec7b69668b33109912..917a5127e433d4a07a788e875f67b98807f2f738 100644
--- a/extensions/common/manifest_constants.cc
+++ b/extensions/common/manifest_constants.cc
@@ -262,9 +262,12 @@ const char kCannotAccessAboutUrl[] =
 const char kCannotAccessChromeUrl[] = "Cannot access a chrome:// URL";
 const char kCannotAccessExtensionUrl[] =
     "Cannot access a chrome-extension:// URL of different extension";
+// This deliberately does not contain a URL. Otherwise an extension can parse
+// error messages and determine the URLs of open tabs without having appropriate
+// permissions to see these URLs.
 const char kCannotAccessPage[] =
-    "Cannot access contents of url \"*\". "
-    "Extension manifest must request permission to access this host.";
+    "Cannot access contents of a page. "

[Devlin, 2015/11/06 20:00:39]

Hmm... I might prefer to have two error messages here - one for if the extension
has tabs permission, and for otherwise, because knowing the host is rather
helpful.  Since all the permission checks boil down to two places, it seems like
it should be pretty easy to do?

[battre, 2015/11/06 21:44:17]

For PermissionsData::CanRunOnPage() that should be trivial. For the
programmatic_script_injector.cc, I am not sure how to go about this. What would
you suggest as a strategy? Should I send the tabs permission as an attribute to
ExtensionMsg_ExecuteCode_Params and memorize it?

[Devlin, 2015/11/06 22:06:13]

Ah, right, I forgot how much of a rat's nest the injection code is. :(

We actually have extension permissions on the renderer side, so we can just
check them.  The problem is *getting* to them.  In some way or another, the
ProgrammaticScriptInjector should check the extension's permissions in order to
generate the error.  The right-est way of doing this might be to pass in an
error to OnWillNotInject that's set from the CanExecuteScriptOnFrame call.  Or
passing in the InjectionHost to OnWillNotInject, and putting a method
GetAccessDeniedError on InjectionHost.

Sorry for the hassle.  If you don't think it's worth it, feel free to add a
TODO.  It's a nice-to-have, but not necessary.

[battre, 2015/11/11 13:31:17]

I have added a TODO. This is a slightly bigger undertaking. We should try to
make the M48 cutoff.

I think that passing the InjectionHost to OnWillNotInject could be an approach.
Either by having a "std::string GetAccessDeninedError(InjectFailureReason
reason, GURL url, GURL effective_url)" function which would cause some code
dupliction for all InjectionHosts or by adding a bool MayReportUrlInError()
function. I think that the latter would be simpler.

[Devlin, 2015/11/11 16:50:47]

Okay, TODO is fine with me.

+    "Extension manifest must request permission to access the respective host.";
 const char kCannotChangeExtensionID[] =
     "Installed extensions cannot change their IDs.";
 const char kCannotClaimAllHostsInExtent[] =