Rewrite YouTube Flash embeds

chrome/renderer/chrome_content_renderer_client.cc

Index: chrome/renderer/chrome_content_renderer_client.cc
diff --git a/chrome/renderer/chrome_content_renderer_client.cc b/chrome/renderer/chrome_content_renderer_client.cc
index 2f4ebe61c9e84f915ea5ff91c494ed572651d63a..4fc167dcb33736d5d3dba660e8892b95fcae7a31 100644
--- a/chrome/renderer/chrome_content_renderer_client.cc
+++ b/chrome/renderer/chrome_content_renderer_client.cc
@@ -21,6 +21,7 @@
 #include "base/values.h"
 #include "build/build_config.h"
 #include "chrome/common/channel_info.h"
+#include "chrome/common/chrome_features.h"
 #include "chrome/common/chrome_isolated_world_ids.h"
 #include "chrome/common/chrome_paths.h"
 #include "chrome/common/chrome_switches.h"
@@ -1379,3 +1380,47 @@ bool ChromeContentRendererClient::ShouldEnforceWebRTCRoutingPreferences() {
   return true;
 #endif
 }
+
+std::string ChromeContentRendererClient::OverrideFlashEmbedWithHTML(
+    const std::string& str_url) {
+
+  if (str_url.empty())
+    return "";

[mlamouri (slow - plz ping), 2016/07/30 17:46:06]

Instead of checking if the string is empty, could you check below if `url` is
invalid?

[kdsilva, 2016/08/01 12:42:44]

Done.

+
+  if (!base::FeatureList::IsEnabled(features::kOverrideYouTubeFlashEmbed))
+    return "";
+
+  GURL url = GURL(str_url);

[mlamouri (slow - plz ping), 2016/07/30 17:46:06]

Maybe add:
```
if (!url.is_valid())
  return "";
```

instead of the early return above?

[kdsilva, 2016/08/01 12:42:44]

Done.

+
+  // We'll only modify YouTube Flash embeds. The URLs can be recognized since
+  // they're in the following form: youtube.com/v/VIDEO_ID. So, we check to see
+  // if the given URL does follow that format. We don't modify
+  // any URLs that contain the enablejsapi=1 parameter since the page may be
+  // interacting with the YouTube Flash player in Javascript and we don't
+  // want to break working content.
+  if (!url.DomainIs("youtube.com") || url.path().find("/v/") != 0
+      || str_url.find("enablejsapi=1") != std::string::npos)
+    return "";
+
+  std::string ret_url = str_url;
+  ret_url.replace(ret_url.find("/v/"), 3, "/embed/");
+
+  // If the website is using an invalid YouTube URL, we'll try and
+  // fix the URL by ensuring that if there are multiple parameters,
+  // the parameter string begins with a "?" and then follows with a "&"
+  // for each subsequent parameter.
+  size_t index = ret_url.find_first_of("&?");
+  bool invalid_url = index != std::string::npos && ret_url.at(index) == '&';
+
+  if (!invalid_url)
+    return ret_url;
+
+  // ? should appear first before all parameters
+  ret_url.replace(index, 1, "?");
+
+  // Replace all instances of ? (after the first) with &
+  for (size_t pos = index + 1;
+        (pos= ret_url.find("?",pos )) != std::string::npos; pos += 1)
+      ret_url.replace(pos, 1, "&");
+  return ret_url;
+}