Allow only responsive websites to install as a web app on mobile.

chrome/browser/android/banners/app_banner_data_fetcher_android.cc

Index: chrome/browser/android/banners/app_banner_data_fetcher_android.cc
diff --git a/chrome/browser/android/banners/app_banner_data_fetcher_android.cc b/chrome/browser/android/banners/app_banner_data_fetcher_android.cc
index bc0662e525468c2699d13089971faae2f81b167d..a35f5802282766f11c6579f2f13508a12ccacc8b 100644
--- a/chrome/browser/android/banners/app_banner_data_fetcher_android.cc
+++ b/chrome/browser/android/banners/app_banner_data_fetcher_android.cc
@@ -4,10 +4,24 @@
 
 #include "chrome/browser/android/banners/app_banner_data_fetcher_android.h"
 
+#include <vector>
+
+#include "base/strings/string_util.h"
 #include "chrome/browser/android/banners/app_banner_infobar_delegate.h"
 #include "chrome/browser/ui/android/infobars/app_banner_infobar.h"
+#include "chrome/common/chrome_constants.h"
+#include "chrome/common/render_messages.h"
 #include "third_party/skia/include/core/SkBitmap.h"
 
+namespace {
+
+const char kMetaViewportTagName[] = "viewport";

[gone, 2015/05/27 22:53:35]

Should ask Paul Kinlan about formatting.  Curious if there are variants that
aren't being considered here.

[dominickn (DO NOT USE), 2015/06/05 07:42:59]

Ben found some code in the compositor which seems to do the checks we want
(https://code.google.com/p/chromium/codesearch#chromium/src/content/browser/re...),
but it's buried pretty deeply in there, and I couldn't work out a simple way of
getting to it from here.

I agree that this implementation is not a great way of checking responsiveness.
I've tried to make it as flexible as possible, but it feels a bit like a hack.
I'd like to find something more robust - preferably a synchronous call into
blink.

+const char kMetaViewportWidthDevice[] = "width=device-width";
+const char kMetaViewportInitialScaleInt[] = "initial-scale=1";
+const char kMetaViewportInitialScaleFloat[] = "initial-scale=1.0";
+
+}  // anonymous namespace
+
 namespace banners {
 
 AppBannerDataFetcherAndroid::AppBannerDataFetcherAndroid(
@@ -36,6 +50,26 @@ bool AppBannerDataFetcherAndroid::ContinueFetching(
   return FetchIcon(image_url);
 }
 
+bool AppBannerDataFetcherAndroid::OnMessageReceived(
+    const IPC::Message& message) {
+  bool handled = true;
+  IPC_BEGIN_MESSAGE_MAP(AppBannerDataFetcherAndroid, message)
+    IPC_MESSAGE_HANDLER(ChromeViewHostMsg_DidRetrieveMetaTagContent,
+                        OnDidRetrieveMetaTagContent)
+    IPC_MESSAGE_UNHANDLED(handled = false)
+  IPC_END_MESSAGE_MAP()
+  return handled;
+}
+
+void AppBannerDataFetcherAndroid::Start(const GURL& validated_url) {
+  validated_url_ = validated_url;
+  is_active_ = true;
+  is_responsive_ = false;
+
+  Send(new ChromeViewMsg_RetrieveMetaTagContent(routing_id(), validated_url,
+                                                kMetaViewportTagName));
+}
+
 std::string AppBannerDataFetcherAndroid::GetAppIdentifier() {
   return native_app_data_.is_null()
       ? AppBannerDataFetcher::GetAppIdentifier() : native_app_package_;
@@ -73,4 +107,33 @@ infobars::InfoBar* AppBannerDataFetcherAndroid::CreateBanner(
   return infobar;
 }
 
+void AppBannerDataFetcherAndroid::OnDidRetrieveMetaTagContent(
+    bool success,
+    const std::string& tag_name,
+    const std::string& tag_content,
+    const GURL& expected_url) {
+

[gone, 2015/05/27 22:53:35]

nit: remove newline

+  if (success && tag_name == kMetaViewportTagName &&
+      validated_url_ == expected_url &&
+      tag_content.size() <= chrome::kMaxMetaTagAttributeLength) {
+    std::string local_tag_content;
+    std::vector<std::string> content_tokens;
+
+    base::RemoveChars(tag_content, " ", &local_tag_content);
+    base::StringToLowerASCII(&local_tag_content);
+    Tokenize(local_tag_content, ",", &content_tokens);
+
+    for (auto property : content_tokens) {
+      if (property == kMetaViewportWidthDevice ||
+          property == kMetaViewportInitialScaleInt ||
+          property == kMetaViewportInitialScaleFloat) {
+        is_responsive_ = true;
+        break;
+      }
+    }
+  }
+
+  AppBannerDataFetcher::Start(validated_url_);
+}
+
 }  // namespace banners