Upstream accessibility font size preferences.

chrome/android/java/src/org/chromium/chrome/browser/accessibility/FontSizePrefs.java

Index: chrome/android/java/src/org/chromium/chrome/browser/accessibility/FontSizePrefs.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/accessibility/FontSizePrefs.java b/chrome/android/java/src/org/chromium/chrome/browser/accessibility/FontSizePrefs.java
new file mode 100644
index 0000000000000000000000000000000000000000..5f3433cce5221500e03b816b736edb5f8f669147
--- /dev/null
+++ b/chrome/android/java/src/org/chromium/chrome/browser/accessibility/FontSizePrefs.java
@@ -0,0 +1,182 @@
+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package org.chromium.chrome.browser.accessibility;
+
+import android.content.Context;
+import android.content.SharedPreferences;
+import android.preference.PreferenceManager;
+
+import org.chromium.base.CalledByNative;
+import org.chromium.base.NativeCall;
+import org.chromium.base.ThreadUtils;
+import org.chromium.chrome.browser.profiles.Profile;
+
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * Interface for Font Scale Factor, Force Enable Zoom, and User Set Force Enable Zoom preferences.

[nyquist, 2014/08/06 23:39:25]

This is not an interface. Could you try to describe what these preferences are
used for? How do they work together? What happens if you change them?

[sunangel, 2014/08/07 18:50:53]

Okay tried to describe it better. 
They are not so On 2014/08/06 23:39:25, nyquist wrote:

+ */
+public class FontSizePrefs {
+    public static final String PREF_FORCE_ENABLE_ZOOM = "force_enable_zoom";
+    public static final String PREF_TEXT_SCALE = "text_scale";
+    public static final String PREF_USER_SET_FORCE_ENABLE_ZOOM = "user_set_force_enable_zoom";
+
+    private final long mFontSizePrefsAndroidPtr;
+    private final Profile mProfile;
+    private final SharedPreferences mSharedPreferences;
+    private final Map<Observer, FontSizePrefsObserverWrapper> mObserverMap;
+    private final static HashMap<Profile, FontSizePrefs> sFontSizeMap =

[nyquist, 2014/08/06 23:39:25]

static before members.

[sunangel, 2014/08/07 18:50:53]

Done.

+            new HashMap<Profile, FontSizePrefs>();
+
+    /*

[nyquist, 2014/08/06 23:39:25]

/** throughout this file for these style comments.

[sunangel, 2014/08/07 18:50:53]

Done.

+     * Observer interface for observing changes in FontScaleFactor and ForceEnableZoom. Note that
+     * this observer does not observe changes in UserSetForceEnableZoom.

[nyquist, 2014/08/06 23:39:25]

Why? This sounds unreasonable.

[sunangel, 2014/08/07 18:50:53]

Haha okay changed this. 
On 2014/08/06 23:39:25, nyquist wrote:

+     */
+    public interface Observer {
+        void onChangeFontSize(float newFontSize);
+        void onChangeForceEnableZoom(boolean enabled);
+    }
+
+    /*
+     * Wrapper for FontSizePrefsObserverAndroid.
+     */
+    public static class FontSizePrefsObserverWrapper {

[nyquist, 2014/08/06 23:39:25]

can this class be private?

[sunangel, 2014/08/07 18:50:53]

Done.

+        private final Observer mFontSizePrefsObserver;
+        private final long mNativeFontSizePrefsObserverWrapperPtr;
+
+        public FontSizePrefsObserverWrapper(Observer observer) {
+            mNativeFontSizePrefsObserverWrapperPtr = nativeInitObserverAndroid();
+            mFontSizePrefsObserver = observer;
+        }
+
+        public long getNativePtr() {
+            return mNativeFontSizePrefsObserverWrapperPtr;
+        }
+
+        public void destroy() {
+            nativeDestroyObserverAndroid(mNativeFontSizePrefsObserverWrapperPtr);
+        }
+
+        @CalledByNative("FontSizePrefsObserverWrapper")
+        public void onChangeFontSize(float newFontSize) {
+            mFontSizePrefsObserver.onChangeFontSize(newFontSize);
+        }
+
+        @CalledByNative("FontSizePrefsObserverWrapper")
+        public void onChangeForceEnableZoom(boolean enabled) {
+            mFontSizePrefsObserver.onChangeForceEnableZoom(enabled);
+        }
+
+        @NativeCall("FontSizePrefsObserverWrapper")
+        private native long nativeInitObserverAndroid();
+
+        @NativeCall("FontSizePrefsObserverWrapper")
+        private native void nativeDestroyObserverAndroid(long nativeFontSizePrefsObserverAndroid);
+    }
+
+    public FontSizePrefs(Profile profile, Context context) {

[nyquist, 2014/08/06 23:39:25]

private?

[sunangel, 2014/08/07 18:50:53]

Done.

+        mProfile = profile;
+        mSharedPreferences = PreferenceManager.getDefaultSharedPreferences(context);

[nyquist, 2014/08/06 23:39:26]

Shouldn't there be an observer for the shared preferences in this class? Maybe
add it in the constructor? See
http://developer.android.com/reference/android/content/SharedPreferences.OnSh...

[sunangel, 2014/08/07 18:50:53]

Done.

+        mFontSizePrefsAndroidPtr = nativeInit(profile);
+        mObserverMap = new HashMap<Observer, FontSizePrefsObserverWrapper>();
+    }
+
+    /*
+     * Returns the FontSizePrefs corresponding to the inputted Profile. If no FontSizePrefs existed,
+     * this method will create one.
+     */
+    public static FontSizePrefs getForProfile(Profile profile, Context context) {
+        ThreadUtils.assertOnUiThread();
+        FontSizePrefs fontSizePrefs = sFontSizeMap.get(profile);
+        if (fontSizePrefs == null) {
+            fontSizePrefs = new FontSizePrefs(profile, context);
+            sFontSizeMap.put(profile, fontSizePrefs);
+        }
+        return fontSizePrefs;
+    }
+
+    /*
+     * Adds the observer to listen for Font Scale and Force Enable Zoom preferences.
+     * @return true if the observerMap was changed as a result of the call.
+     */
+    public boolean addObserver(Observer obs) {
+        if (mObserverMap.containsKey(obs)) return false;
+        FontSizePrefsObserverWrapper wrappedObserver =
+                new FontSizePrefsObserverWrapper(obs);
+        nativeAddObserver(mFontSizePrefsAndroidPtr, wrappedObserver.getNativePtr());
+        mObserverMap.put(obs, wrappedObserver);
+        return true;
+    }
+
+    /*
+     * Removes the observer and unregisters it from Font Scale and Force Enable Zoom changes.
+     * @return true if an observer was removed as a result of the call.
+     */
+    public boolean removeObserver(Observer obs) {
+        FontSizePrefsObserverWrapper wrappedObserver = mObserverMap.remove(obs);
+        if (wrappedObserver == null) return false;
+        nativeRemoveObserver(mFontSizePrefsAndroidPtr, wrappedObserver.getNativePtr());
+        wrappedObserver.destroy();
+        return true;
+    }
+
+    /*
+     * Sets UserSetForceEnableZoom. This is the only one of three preferences stored through
+     * SharedPreferences.
+     */
+    public void setUserSetForceEnableZoom(boolean enabled) {
+        SharedPreferences.Editor sharedPreferencesEditor = mSharedPreferences.edit();
+        sharedPreferencesEditor.putBoolean(PREF_USER_SET_FORCE_ENABLE_ZOOM, enabled);

[nyquist, 2014/08/06 23:39:25]

Are these per profile? I don't think they are, and in that case, I believe we
should probably just have a singleton instance of this class instead of a map of
them. :-( Which means getInstance(Context context) method.

Another thing you could do, is do what I described here first, and then add a
migration step for old users downstream separately, and make this then be keyed
off profile.

[sunangel, 2014/08/07 18:50:53]

Done.

+        sharedPreferencesEditor.apply();
+    }
+
+    /*
+     * Returns true if user has manually set ForceEnableZoom and false otherwise.
+     */
+    public boolean getUserSetForceEnableZoom() {
+        return mSharedPreferences.getBoolean(PREF_USER_SET_FORCE_ENABLE_ZOOM,
+                false);
+    }
+
+    public void setFontScaleFactor(float fontScaleFactor) {
+        nativeSetFontScaleFactor(mFontSizePrefsAndroidPtr, fontScaleFactor);
+    }
+
+    public float getFontScaleFactor() {
+        return nativeGetFontScaleFactor(mFontSizePrefsAndroidPtr);
+    }
+
+    public void setForceEnableZoom(boolean enabled) {
+        nativeSetForceEnableZoom(mFontSizePrefsAndroidPtr, enabled);
+    }
+
+    public boolean getForceEnableZoom() {
+        return nativeGetForceEnableZoom(mFontSizePrefsAndroidPtr);
+    }
+
+    public void destroy() {
+        sFontSizeMap.remove(mProfile);
+        nativeDestroy(mFontSizePrefsAndroidPtr);
+    }
+
+    private native void nativeAddObserver(long nativeFontSizePrefsAndroid,
+            long nativeObserverPtr);
+
+    private native void nativeRemoveObserver(long nativeFontSizePrefsAndroid,
+            long nativeObserverPtr);
+
+    private native long nativeInit(Profile profile);
+
+    private native void nativeDestroy(long nativeFontSizePrefsAndroid);
+
+    private native void nativeSetFontScaleFactor(long nativeFontSizePrefsAndroid, float font);
+
+    private native float nativeGetFontScaleFactor(long nativeFontSizePrefsAndroid);
+
+    private native boolean nativeGetForceEnableZoom(long nativeFontSizePrefsAndroid);
+
+    private native void nativeSetForceEnableZoom(long nativeFontSizePrefsAndroid, boolean enabled);
+}