predictors: Add resource type to manifest.

components/precache/core/proto/precache.proto

Index: components/precache/core/proto/precache.proto
diff --git a/components/precache/core/proto/precache.proto b/components/precache/core/proto/precache.proto
index 2e9aec257eba888885ead0edb2ea113a006b963f..f8a10c0e729b813255b1a7d01a8859e26e7a2826 100644
--- a/components/precache/core/proto/precache.proto
+++ b/components/precache/core/proto/precache.proto
@@ -26,6 +26,20 @@ message PrecacheResource {
   // This is a non-negative number, with higher being more important. Its value
   // depends on PrecacheConfigurationSettings.resource_weight_function.
   optional double weight = 4;
+
+  enum Type {
+    RESOURCE_TYPE_UNKNOWN = 0;
+
+    RESOURCE_TYPE_IMAGE = 1;
+    RESOURCE_TYPE_FONT = 2;
+    RESOURCE_TYPE_STYLESHEET = 3;
+    RESOURCE_TYPE_SCRIPT = 4;
+
+    RESOURCE_TYPE_OTHER = 7;
+  }
+
+  // The type of resource.
+  optional Type type = 5;

[Benoit L, 2017/04/27 08:54:15]

Does the precache code need to be updated in any way?

[alexilin, 2017/04/27 15:32:23]

I don't think so. This field was in real manifests for a while as unknown_field
and declaring it explicitly in .proto shouldn't change anything. 

 };
 
 message PrecacheManifestId {