Add calls to the server to request WebAPK updates.

chrome/browser/android/webapk/webapk.proto

Index: chrome/browser/android/webapk/webapk.proto
diff --git a/chrome/browser/android/webapk/webapk.proto b/chrome/browser/android/webapk/webapk.proto
index 54adaf792b928bc1d4970ef8f84fc7b452a48864..2d8d141464c68ee7113855337a9661035a4cb250 100644
--- a/chrome/browser/android/webapk/webapk.proto
+++ b/chrome/browser/android/webapk/webapk.proto
@@ -14,29 +14,47 @@ message CreateWebApkRequest {
   optional WebApk webapk = 1;
 }
 
-// Response to CreateWebApkRequest.
-message CreateWebApkResponse {
+// Creates a updated WebAPK on the server and returns URL to download WebAPK
+// from Google Play.
+message UpdateWebApkRequest {
+  optional WebApk webapk = 1;
+}
+
+// Response after creating or updating a WebAPK.
+message WebApkResponse {

[pkotwicz, 2016/08/02 21:05:04]

I think that we should either:
- Have a different "create WebAPK proto" and a different "update WebAPK" proto
and have a different "create WebAPK response" proto and a different "update
WebAPK response" proto

OR

- Have the same proto for "Creating WebAPKs" and for "Updating WebAPKs" and have
the same proto for the "Create WebAPK response" and for the "Update WebAPK
response"

[Xi Han, 2016/08/03 17:30:05]

As discussed offline, just keep the proto the same as what the server declared.

   // Package name to install WebAPK at.
   optional string webapk_package_name = 1;
 
-  // URL to download WebAPK.
-  optional string signed_download_url = 2;
+  // Version code of the WebAPK.
+  optional string version = 2;
+
+  // URL to download WebAPK from Google Play.
+  optional string signed_market_url = 5;

[pkotwicz, 2016/08/03 01:07:06]

In the new world, Chrome is responsible for downloading the WebAPK not the
Google Play server. In this new world, I think that |signed_download_url| makes
more sense than |signed_market_url|

Yes, the name of the field on the server needs to be updated

[Xi Han, 2016/08/03 17:30:05]

Done.

+
+  // Warnings regarding the creation or update of the WebAPK, if any.
+  repeated string warnings = 4;

[pkotwicz, 2016/08/03 01:07:06]

We do not seem to be using this field. Let's skip it for now and use the
|reserved| keyword

[Xi Han, 2016/08/03 17:30:04]

Done.

 }
 
 message WebApk {
+  // Package name of the WebAPK.
+  optional string package_name = 1;
+
+  // Version code of the WebAPK.
+  optional string version = 2;

[pkotwicz, 2016/08/02 21:05:04]

You do not seem to send this field in webapk_installer.cc

[Xi Han, 2016/08/03 17:30:05]

Good catch, added.

+
   // The URL of the Web App Manifest.
-  optional string manifest_url = 2;
+  optional string manifest_url = 3;
 
   // Chrome's package name.
-  optional string requester_application_package = 4;
+  optional string requester_application_package = 5;
 
   // Chrome's version.
-  optional string requester_application_version = 5;
+  optional string requester_application_version = 6;
 
   // The Web App Manifest.
-  optional WebAppManifest manifest = 6;
+  optional WebAppManifest manifest = 7;
 
-  reserved 1, 3, 7;
+  reserved 4;
 }
 
 // Contains data from the Web App Manifest.