Enforce the page title direction

content/renderer/render_view.cc

Index: content/renderer/render_view.cc
diff --git a/content/renderer/render_view.cc b/content/renderer/render_view.cc
index d0f09c703dba14c6bb62ff57a311adcc066ab4d2..a51719e9c2c6642b6027d632fc561a1de7ec02e1 100644
--- a/content/renderer/render_view.cc
+++ b/content/renderer/render_view.cc
@@ -12,6 +12,7 @@
 #include "base/callback.h"
 #include "base/command_line.h"
 #include "base/compiler_specific.h"
+#include "base/i18n/rtl.h"
 #include "base/json/json_writer.h"
 #include "base/lazy_instance.h"
 #include "base/metrics/histogram.h"
@@ -242,6 +243,18 @@ using webkit_glue::WebAccessibility;
 
 //-----------------------------------------------------------------------------
 
+namespace {
+
+// Return true if the character is known to be a strong LTR character.
+// A false return value can mean it's not an LTR character or just that
+// it's a strongly LTR character not in the set we test.
+// Used as a fast-path for the common case of LTR text.
+bool IsStronglyLTR(char16 ch) {

[brettw, 2011/07/29 17:14:00]

If the check in rtl.h is slow, it seems like it might be worthwhile to move this
function in there so everybody calling the Wrap function can take advantage of
the fast path.

It might also be nice to name this "Fast" or something since it doesn't actually
do a real check for strong LTR (which would be more complex & slow).

[Evan Martin, 2011/07/30 00:05:15]

It's more that the function in rtl.h actually scans the string looking for a
strongly directional character, while in this code I'm interested in whether the
*first* character is strongly RTL.

I will try to think of a better name.

+  return (ch >= 'A' && ch <= 'Z') || (ch >= 'a' && ch <= 'z');
+}
+
+}  // namespace
+
 typedef std::map<WebKit::WebView*, RenderView*> ViewMap;
 static base::LazyInstance<ViewMap> g_view_map(base::LINKER_INITIALIZED);
 
@@ -1177,15 +1190,27 @@ void RenderView::UpdateURL(WebFrame* frame) {
 }
 
 // Tell the embedding application that the title of the active page has changed
-void RenderView::UpdateTitle(WebFrame* frame, const string16& title) {
-  // Ignore all but top level navigations...
-  if (!frame->parent()) {
-    Send(new ViewHostMsg_UpdateTitle(
-        routing_id_,
-        page_id_,
-        title.length() > content::kMaxTitleChars ?
-            title.substr(0, content::kMaxTitleChars) : title));
+void RenderView::UpdateTitle(WebFrame* frame, const string16& title,
+                             WebTextDirection title_direction) {
+  // Ignore all but top level navigations.
+  if (frame->parent())
+    return;
+
+  string16 fixed_title = title.substr(0, content::kMaxTitleChars);
+
+  // Wrap with extra Unicode formatting to make the title strongly directional.
+  if (!fixed_title.empty()) {
+    if (title_direction == WebKit::WebTextDirectionLeftToRight) {
+      // To avoid needing to complicate tests that only use ASCII characters,
+      // special-case out some known strongly directional characters.
+      if (!IsStronglyLTR(title[0]))
+        base::i18n::WrapStringWithLTRFormatting(&fixed_title);
+    } else {
+      base::i18n::WrapStringWithRTLFormatting(&fixed_title);
+    }
   }
+
+  Send(new ViewHostMsg_UpdateTitle(routing_id_, page_id_, fixed_title));
 }
 
 void RenderView::UpdateEncoding(WebFrame* frame,
@@ -2530,9 +2555,7 @@ void RenderView::didCreateDocumentElement(WebFrame* frame) {
 
 void RenderView::didReceiveTitle(WebFrame* frame, const WebString& title,
                                  WebTextDirection direction) {
-  // TODO: pass direction through various APIs.
-  // http://code.google.com/p/chromium/issues/detail?id=79903
-  UpdateTitle(frame, title);
+  UpdateTitle(frame, title, direction);
 
   // Also check whether we have new encoding name.
   UpdateEncoding(frame, frame->view()->pageEncoding().utf8());
@@ -2597,7 +2620,11 @@ void RenderView::didNavigateWithinPage(
 
   didCommitProvisionalLoad(frame, is_new_navigation);
 
-  UpdateTitle(frame, frame->view()->mainFrame()->dataSource()->pageTitle());
+  // TODO(evan): update this to use ->pageTitleDirection() once we pull in new
+  // WebKit.
+  // http://code.google.com/p/chromium/issues/detail?id=27094
+  UpdateTitle(frame, frame->view()->mainFrame()->dataSource()->pageTitle(),
+              WebKit::WebTextDirectionLeftToRight);
 }
 
 void RenderView::didUpdateCurrentHistoryItem(WebFrame* frame) {