Make Jinja variable names consistent.

Rename the minimum/target SDK version and manifest package name
variables in the WebView manifest to be consistent with the ones in the
Chrome manifest. Use the old names as a default value so as not to break
downstream until this is updated.

Change-Id: If55711db4540fc164ddd0f6bddcf30abd3da99a5
Reviewed-on: https://chromium-review.googlesource.com/1241014Reviewed-by: Changwan Ryu <changwan@chromium.org>
Commit-Queue: Richard Coles <torne@chromium.org>
Cr-Commit-Position: refs/heads/master@{#593658}

android_webview/BUILD.gn

@@ -106,7 +106,7 @@ java_cpp_enum("aw_safe_browsing_action") {
 jinja_template("system_webview_manifest") {
   input = "apk/java/AndroidManifest.xml"
   output = system_webview_android_manifest
-  variables = [ "package=$system_webview_package_name" ]
+  variables = [ "manifest_package=$system_webview_package_name" ]
 }
 
 webview_repack_locales("repack_locales") {

android_webview/apk/java/AndroidManifest.xml

@@ -7,10 +7,10 @@
 
 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
     xmlns:tools="http://schemas.android.com/tools"
-    package="{{package|default('com.android.webview')}}"
+    package="{{manifest_package|default(package)|default('com.android.webview')}}"
     tools:ignore="MissingLeanbackLauncher">
-    <uses-sdk android:minSdkVersion="{{minsdk|default(21)}}"
-              android:targetSdkVersion="{{targetsdk|default(28)}}">
+    <uses-sdk android:minSdkVersion="{{min_sdk_version|default(minsdk)|default(21)}}"
+              android:targetSdkVersion="{{target_sdk_version|default(targetsdk)|default(28)}}">
     </uses-sdk>
 
     <uses-feature android:name="android.hardware.touchscreen"
@@ -22,7 +22,7 @@
     <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
 
     <application android:label="Android System WebView"
-                 android:icon="@{{package|default('com.android.webview')}}:drawable/icon_webview"
+                 android:icon="@{{manifest_package|default(package)|default('com.android.webview')}}:drawable/icon_webview"
                  android:name="{{ application_name|default('com.android.webview.chromium.WebViewApplication') }}"
                  android:multiArch="true"
                  android:use32bitAbi="true">
@@ -61,7 +61,7 @@
                          android:process=":webview_service" />
             {% endif %}
         {% endmacro %}
-        {{ common(package|default('com.android.webview'), library|default('libwebviewchromium.so')) }}
+        {{ common(manifest_package|default(package)|default('com.android.webview'), library|default('libwebviewchromium.so')) }}
         {% if donor_package is defined %}
             <meta-data android:name="com.android.webview.WebViewDonorPackage"
                        android:value="{{ donor_package }}" />