[android_webview] Enable navigation interception for iframes.

android_webview/browser/renderer_host/aw_resource_dispatcher_host_delegate.cc

Index: android_webview/browser/renderer_host/aw_resource_dispatcher_host_delegate.cc
diff --git a/android_webview/browser/renderer_host/aw_resource_dispatcher_host_delegate.cc b/android_webview/browser/renderer_host/aw_resource_dispatcher_host_delegate.cc
index b24eb2b56eac50e61bccdadb308a07a74515d6c0..328cecf30f5e2d69e86b84336118844603d64e20 100644
--- a/android_webview/browser/renderer_host/aw_resource_dispatcher_host_delegate.cc
+++ b/android_webview/browser/renderer_host/aw_resource_dispatcher_host_delegate.cc
@@ -130,7 +130,22 @@ void AwResourceDispatcherHostDelegate::RequestBeginning(
   throttles->push_back(new MaybeCancelResourceThrottle(
       child_id, route_id, request));
 
-  if (resource_type == ResourceType::MAIN_FRAME) {
+  bool allow_intercepting =
+      // We ignore POST requests because of BUG=155250.

[John Knottenbelt, 2012/11/19 14:09:03]

Can you elaborate a little here why we ignore POST requests. It would be great
to be able to understand without having to go to the bug. Having gone to the
bug, I still didn't really understand why POST requests don't work.

+      request->method() != "POST" &&
+      // We allow intercepting navigations within subframes, but only if the
+      // scheme other than http or https. This is because the embedder
+      // can't distinguish main frame and subframe callbacks (which could lead
+      // to broken content if the embedder decides to not ignore the main frame
+      // navigation, but ignores the subframe navigation).
+      // The reason this is supported at all is that certain JavaScript-based
+      // frameworks use iframe navigation as a form of communication with the
+      // embedder.

[joth, 2012/11/20 20:08:02]

is this a sane thing to support long term? if not, we might want to allow the
glue layer to choose if we do this, and disable it for apps targeting some
future version.

+      (resource_type == ResourceType::MAIN_FRAME ||
+       (resource_type == ResourceType::SUB_FRAME &&
+        !request->url().SchemeIs(chrome::kHttpScheme) &&
+        !request->url().SchemeIs(chrome::kHttpsScheme)));

[joth, 2012/11/20 20:08:02]

nit: maybe easier to read as.

bool allow_intercepting = resource_type == ResourceType::MAIN_FRAME;

if (is allowable sub frame) {
  allow_intercepting = true;
}

+  if (allow_intercepting) {
     throttles->push_back(InterceptNavigationDelegate::CreateThrottleFor(
         request));
   }