Fix strict mode exclusions for WebView prefs.

Anywhere we call getSharedPreferences might be a disk write as the
directory for prefs is created if it doesn't already exist; move the
existing StrictModeContext in AwGeolocationPermissions up to the caller
to also cover where the SharedPreferences object is retrieved, and add
another missing one when the browser context is created.

Bug: 994321
Change-Id: I2e18e156d378910751ee2a530d72180eab012696
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1773781Reviewed-by: Nate Fischer <ntfschr@chromium.org>
Commit-Queue: Richard Coles <torne@chromium.org>
Cr-Commit-Position: refs/heads/master@{#690913}

android_webview/java/src/org/chromium/android_webview/AwBrowserContext.java

@@ -9,6 +9,7 @@ import android.content.SharedPreferences;
 
 import org.chromium.android_webview.common.PlatformServiceBridge;
 import org.chromium.base.ContextUtils;
+import org.chromium.base.StrictModeContext;
 import org.chromium.base.VisibleForTesting;
 import org.chromium.base.annotations.CalledByNative;
 import org.chromium.base.annotations.JNINamespace;
@@ -102,11 +103,17 @@ public class AwBrowserContext {
     }
 
     private void migrateGeolocationPreferences() {
+        try (StrictModeContext ignored = StrictModeContext.allowDiskWrites()) {
+            // Prefs dir will be created if it doesn't exist, so must allow writes
+            // for this and so that the actual prefs can be written to the new
+            // location if needed.
             final String oldGlobalPrefsName = "WebViewChromiumPrefs";
             SharedPreferences oldGlobalPrefs =
                     ContextUtils.getApplicationContext().getSharedPreferences(
                             oldGlobalPrefsName, Context.MODE_PRIVATE);
-        AwGeolocationPermissions.migrateGeolocationPreferences(oldGlobalPrefs, mSharedPreferences);
+            AwGeolocationPermissions.migrateGeolocationPreferences(
+                    oldGlobalPrefs, mSharedPreferences);
+        }
     }
 
     /**
@@ -141,9 +148,12 @@ public class AwBrowserContext {
 
     @CalledByNative
     public static AwBrowserContext create(long nativeAwBrowserContext, boolean isDefault) {
-        SharedPreferences sharedPreferences =
-                ContextUtils.getApplicationContext().getSharedPreferences(
+        SharedPreferences sharedPreferences;
+        try (StrictModeContext ignored = StrictModeContext.allowDiskWrites()) {
+            // Prefs dir will be created if it doesn't exist, so must allow writes.
+            sharedPreferences = ContextUtils.getApplicationContext().getSharedPreferences(
                     CHROMIUM_PREFS_NAME, Context.MODE_PRIVATE);
+        }
 
         return new AwBrowserContext(sharedPreferences, nativeAwBrowserContext, isDefault);
     }

android_webview/java/src/org/chromium/android_webview/AwGeolocationPermissions.java

@@ -6,7 +6,6 @@ package org.chromium.android_webview;
 
 import android.content.SharedPreferences;
 
-import org.chromium.base.StrictModeContext;
 import org.chromium.base.task.PostTask;
 import org.chromium.content_public.browser.UiThreadTaskTraits;
 import org.chromium.net.GURLUtils;
@@ -133,7 +132,6 @@ public final class AwGeolocationPermissions {
     /* package */
     static void migrateGeolocationPreferences(
             SharedPreferences oldPrefs, SharedPreferences newPrefs) {
-        try (StrictModeContext ignored = StrictModeContext.allowDiskWrites()) {
         SharedPreferences.Editor oldPrefsEditor = oldPrefs.edit();
 
         SharedPreferences.Editor newPrefsEditor = newPrefs.edit();
@@ -145,5 +143,4 @@ public final class AwGeolocationPermissions {
             }
         }
     }
-    }
 }