Move the IsSupported* mime functions out of //net and into //components/mime_util

content/browser/frame_host/navigation_controller_impl.cc

Index: content/browser/frame_host/navigation_controller_impl.cc
diff --git a/content/browser/frame_host/navigation_controller_impl.cc b/content/browser/frame_host/navigation_controller_impl.cc
index 8c9f0332d62ca36934acfa1dd85c16691fa8e209..b8753a0978fd65fcfae65b984aaced1a656a96c3 100644
--- a/content/browser/frame_host/navigation_controller_impl.cc
+++ b/content/browser/frame_host/navigation_controller_impl.cc
@@ -14,6 +14,7 @@
 #include "base/time/time.h"
 #include "base/trace_event/trace_event.h"
 #include "cc/base/switches.h"
+#include "components/mime_util/mime_util.h"
 #include "content/browser/bad_message.h"
 #include "content/browser/browser_url_handler_impl.h"
 #include "content/browser/dom_storage/dom_storage_context_wrapper.h"
@@ -493,7 +494,8 @@ NavigationEntryImpl* NavigationControllerImpl::GetLastCommittedEntry() const {
 
 bool NavigationControllerImpl::CanViewSource() const {
   const std::string& mime_type = delegate_->GetContentsMimeType();
-  bool is_viewable_mime_type = net::IsSupportedNonImageMimeType(mime_type) &&
+  bool is_viewable_mime_type =
+      mime_util::IsSupportedNonImageMimeType(mime_type) &&
       !net::IsSupportedMediaMimeType(mime_type);

[servolk, 2015/04/28 23:38:48]

I believe this can be simplified to:

bool is_viewable_mime_type = mime_util::IsSupportedNonImageMimeType(mime_type);

Before your change net::IsSupportedNonImageMimeType used to return true for
media mime types (e.g. 'video/webm'), because common_media_types used to be
inserted into MimeUtil::non_image_map_ at
https://code.google.com/p/chromium/codesearch#chromium/src/net/base/mime_util....
But after your change mime_util::non_image_map_ no longer contains
common_media_types, and so there's no need to exclude
net::IsSupportedMediaMimeType explicitly here.
Also, strictly speaking this changes semantics of IsSupportedNonImageMimeType,
so we should look carefully at all 3 places where IsSupportedNonImageMimeType is
being used, other than unit tests. E.g. we should probably change
SimpleWebMimeRegistryImpl::supportsNonImageMIMEType to include
common_media_types, to make sure behavior is preserved on blink level.

[asanka, 2015/04/29 02:26:37]

The behavior is preserved by having mime_util::IsSupportedNonImageMimeType()
call into net::IsSupportedMediaMimeType(). Can you doublecheck?

[Ryan Sleevi, 2015/04/29 05:29:07]

Right, Sergey, I'm not quite sure I follow - the media map and modifications are
still preserved by having IsSupportedMediaMimeType call, which is effectively
all the non_image_map_ was doing. Could you double check your analysis and let
us know if we've missed something?

   NavigationEntry* visible_entry = GetVisibleEntry();
   return visible_entry && !visible_entry->IsViewSourceMode() &&