Add support for icons.{src,type,density} in Manifest.

content/public/common/manifest.h

Index: content/public/common/manifest.h
diff --git a/content/public/common/manifest.h b/content/public/common/manifest.h
index 35a49b138a68b490365b8cd93e0b0eb55952d9d5..93bd342399a6e33c8bd08d95140d416b0f3e2aec 100644
--- a/content/public/common/manifest.h
+++ b/content/public/common/manifest.h
@@ -5,6 +5,8 @@
 #ifndef CONTENT_PUBLIC_COMMON_MANIFEST_H_
 #define CONTENT_PUBLIC_COMMON_MANIFEST_H_
 
+#include <vector>
+
 #include "base/strings/nullable_string16.h"
 #include "content/common/content_export.h"
 #include "third_party/WebKit/public/platform/WebScreenOrientationLockType.h"
@@ -24,6 +26,29 @@ struct CONTENT_EXPORT Manifest {
     DISPLAY_MODE_BROWSER
   };
 
+  // Structure representing an icon as per the Manifest specification, see:
+  // http://w3c.github.io/manifest/#dfn-icon-object
+  struct Icon {
+    Icon();
+    ~Icon();
+
+    // MUST be a valid url. If an icon doesn't have a valid URL, it will not be
+    // successfully parsed, thus will not be represented in the Manifest.
+    GURL src;
+
+    // Null if the parsing failed or the field was not present. The type can be
+    // any string and doesn't have to be a valid image MIME type at this point.
+    // It is up to the consumer of the object to check if the type matches a
+    // supported type.
+    base::NullableString16 type;

[palmer, 2014/09/22 20:35:43]

Ultimately, I'd expect the interface to "harden", and for this to become an
enum. How many possible MIME types do we really expect? Can we harden the
interface now, or soon?

Why not std::string?

[mlamouri (slow - plz ping), 2014/09/22 21:09:31]

It's NullableString16 because the type might not be specified. It is an optional
information. This is the same reason why the interface isn't hardened: the final
consumer of that information might want to behave differently with regards to
missing or bogus values.

+
+    // Default value is 1.0 if the value is missing or invalid.
+    double density;
+
+    // Default density. Set to 1.0.
+    static const double kDefaultDensity;
+  };
+
   Manifest();
   ~Manifest();
 
@@ -48,6 +73,10 @@ struct CONTENT_EXPORT Manifest {
   // field was not present.
   blink::WebScreenOrientationLockType orientation;
 
+  // Empty if the parsing failed, the field was not present, empty or all the
+  // icons inside the JSON array were invalid.
+  std::vector<Icon> icons;
+
   // Maximum length for all the strings inside the Manifest when it is sent over
   // IPC. The renderer process should truncate the strings before sending the
   // Manifest and the browser process must do the same when receiving it.