AW: use distinct task affinities for each channel

Previously all WebView providers on the device would use the same
(global) taskAffinity for developer UI. This means launching Dev UI from
one channel would obliterate the previous Dev UI session, re-using the
original channel's icon for the task (which may no longer be correct).

The simplest solution to ensure we always have the right icon is to let
different channels launch in different tasks. We achieve this by using
the package name as part of the taskAffinity. This uses a "." instead of
a ":" delimiter because ":" is apparently an illegal character for
taskAffinity (can't compile).

Fixed: 1060013
Test: Manual - build 2 local builds and verify I can launch each
Test: side-by-side
Change-Id: If8b1def9a4d8af9187a117f39816dcce2c77913b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2095930Reviewed-by: Richard Coles <torne@chromium.org>
Commit-Queue: Nate Fischer <ntfschr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#748885}

android_webview/nonembedded/README.md

@@ -58,4 +58,5 @@ other:
   declare either process depending on what it needs.
 - Activities also need an explicit `android:taskAffinity`, otherwise using the
   WebView Activity will replace the current Chrome session from the task stack
-  (or vice versa).
+  (or vice versa). The taskAffinity should include the WebView package name,
+  otherwise Activities from different WebView channels will trample each other.

android_webview/nonembedded/java/AndroidManifest.xml

@@ -39,7 +39,7 @@
                       android:icon="@drawable/icon_webview"
                       android:theme="@style/Theme.DevUi.DayNight"
                       android:launchMode="singleTask"
-                      android:taskAffinity="org.chromium.android_webview.devui" {# Explicit taskAffinity to distinguish from monochrome browser task. #}
+                      android:taskAffinity="{{ manifest_package }}.org.chromium.android_webview.devui" {# Explicit taskAffinity to distinguish from monochrome browser task. #}
                       android:process=":webview_apk">  {# Explicit process required for monochrome compatibility. #}
                 <intent-filter>
                     <action android:name="com.android.webview.SHOW_DEV_UI" />
@@ -55,14 +55,14 @@
                       android:label="WebView Crashes"
                       android:theme="@style/Theme.DevUi.DayNight"
                       android:launchMode="singleTop"
-                      android:taskAffinity="org.chromium.android_webview.devui" {# Explicit taskAffinity to distinguish from monochrome browser task. #}
+                      android:taskAffinity="{{ manifest_package }}.org.chromium.android_webview.devui" {# Explicit taskAffinity to distinguish from monochrome browser task. #}
                       android:process=":webview_apk">  {# Explicit process required for monochrome compatibility. #}
             </activity>
             <activity android:name="org.chromium.android_webview.devui.FlagsActivity"
                       android:label="WebView Flags"
                       android:theme="@style/Theme.DevUi.DayNight"
                       android:launchMode="singleTop"
-                      android:taskAffinity="org.chromium.android_webview.devui" {# Explicit taskAffinity to distinguish from monochrome browser task. #}
+                      android:taskAffinity="{{ manifest_package }}.org.chromium.android_webview.devui" {# Explicit taskAffinity to distinguish from monochrome browser task. #}
                       android:process=":webview_apk">  {# Explicit process required for monochrome compatibility. #}
             </activity>
             <!-- End of WebView Developer UI Activities -->

chrome/android/java/monochrome_public_bundle__base_bundle_module.AndroidManifest.expected

@@ -1003,7 +1003,7 @@
         android:launchMode="singleTask"
         android:name="org.chromium.android_webview.devui.MainActivity"
         android:process=":webview_apk"
-        android:taskAffinity="org.chromium.android_webview.devui"
+        android:taskAffinity="org.chromium.chrome.org.chromium.android_webview.devui"
         android:theme="@style/Theme.DevUi.DayNight">
       <intent-filter>
         <action android:name="com.android.webview.SHOW_DEV_UI"/>
@@ -1028,7 +1028,7 @@
         android:launchMode="singleTop"
         android:name="org.chromium.android_webview.devui.CrashesListActivity"
         android:process=":webview_apk"
-        android:taskAffinity="org.chromium.android_webview.devui"
+        android:taskAffinity="org.chromium.chrome.org.chromium.android_webview.devui"
         android:theme="@style/Theme.DevUi.DayNight"/>
     <activity
         android:label="WebView
@@ -1036,7 +1036,7 @@
         android:launchMode="singleTop"
         android:name="org.chromium.android_webview.devui.FlagsActivity"
         android:process=":webview_apk"
-        android:taskAffinity="org.chromium.android_webview.devui"
+        android:taskAffinity="org.chromium.chrome.org.chromium.android_webview.devui"
         android:theme="@style/Theme.DevUi.DayNight"/>
     <activity
         android:enabled="false"