Android: address lint warnings.

build/android/lint/suppressions.xml

 <?xml version="1.0" encoding="utf-8"?>
 <lint>
   <!--
 STOP! It looks like you want to suppress some lint errors:
 - Have you tried identifing the offending patch?
   Ask the author for a fix and/or revert the patch.
 - It is preferred to add suppressions in the code instead of
   sweeping it under the rug here. See:
 
     http://developer.android.com/tools/debugging/improving-w-lint.html
 
 Still reading?
 - You can edit this file manually to suppress an issue
   globally if it is not applicable to the project.
 - You can also automatically add issues found so for in the
   build process by running:
 
     build/android/lint/suppress.py
 
   which will generate this file (Comments are not preserved).
   Note: PRODUCT_DIR will be substituted at run-time with actual
   directory path (e.g. out/Debug)
 -->
+  <!-- AllowBackup defaults to true, and causes a lint warning if not explicitly set. -->
   <issue id="AllowBackup">
     <ignore path="AndroidManifest.xml"/>
   </issue>
+  <!-- We use asserts in Chromium. See https://chromium.googlesource.com/chromium/src/+/master/styleguide/java/java.md#Asserts -->
   <issue id="Assert" severity="ignore"/>
-  <!-- TODO(crbug.com/635567): Fix this properly. -->
   <issue id="BadHostnameVerifier" severity="Error">
+    <!-- Safe, used in test only. -->
     <ignore regexp="net/test/android/javatests/src/org/chromium/net/test/util/TestWebServer.java"/>
   </issue>
   <issue id="ButtonOrder" severity="Error">
     <ignore regexp="chrome/android/java/res/layout/homepage_editor.xml"/>
   </issue>
   <issue id="ButtonStyle" severity="Error">
     <ignore regexp="remoting/android/host/res/layout/main.xml"/>
   </issue>
   <issue id="CommitPrefEdits">
     <ignore regexp="third_party/cacheinvalidation/src/java/com/google/ipc/invalidation/ticl/android2/channel/AndroidChannelPreferences.java"/>
@@ skipping 26 matching lines @@
   <!-- TODO(crbug.com/635567): Fix this properly. -->
   <issue id="GoogleAppIndexingUrlError" severity="Error">
     <ignore regexp="AndroidManifest.xml"/>
   </issue>
   <!-- TODO(crbug.com/635567): Fix this properly. -->
   <issue id="GoogleAppIndexingWarning" severity="Error">
     <ignore regexp="AndroidManifest.xml"/>
   </issue>
   <issue id="HandlerLeak">
     <ignore regexp="android_webview/glue/java/src/com/android/webview/chromium/WebViewContentsClientAdapter.java" />
-    <!-- TODO(crbug.com/635567): Fix this properly. -->
-    <ignore regexp="chrome/android/java/src/org/chromium/chrome/browser/compositor/overlays/strip/StripLayoutHelper.java"/>
-    <!-- TODO(crbug.com/635567): Fix this properly. -->
-    <ignore regexp="chrome/android/java/src/org/chromium/chrome/browser/gsa/GSAServiceClient.java"/>
-    <!-- TODO(crbug.com/635567): Fix this properly. -->
-    <ignore regexp="chrome/android/java/src/org/chromium/chrome/browser/tab/Tab.java"/>
     <ignore regexp="chromecast/internal" />
     <ignore regexp="remoting/android/java/src/org/chromium/chromoting/TapGestureDetector.java" />
   </issue>
   <issue id="HardcodedDebugMode" severity="Fatal">
     <ignore path="AndroidManifest.xml"/>
   </issue>
   <issue id="HardcodedText" severity="Error">
     <ignore regexp="chromecast/internal"/>
     <ignore regexp="remoting/android/host/res/layout/main.xml"/>
   </issue>
@@ skipping 361 matching lines @@
   </issue>
   <issue id="ViewConstructor" severity="ignore"/>
   <issue id="WrongCall" severity="ignore"/>
   <issue id="WrongConstant">
     <ignore regexp="chrome/android/java/src/org/chromium/chrome/browser/SSLClientCertificateRequest.java"/>
     <ignore regexp="chrome/android/java/src/org/chromium/chrome/browser/payments/ui/EditorView.java"/>
     <ignore regexp="chrome/android/java/src/org/chromium/chrome/browser/signin/SigninAndSyncView.java"/>
     <ignore regexp="content/public/android/java/src/org/chromium/content/browser/ChildProcessConnectionImpl.java"/>
   </issue>
 </lint>