Add Settings[, Oberser] java code and JNI bridge.

blimp/client/core/settings/android/java/src/org/chromium/blimp/core/settings/Settings.java

Index: blimp/client/core/settings/android/java/src/org/chromium/blimp/core/settings/Settings.java
diff --git a/blimp/client/core/settings/android/java/src/org/chromium/blimp/core/settings/Settings.java b/blimp/client/core/settings/android/java/src/org/chromium/blimp/core/settings/Settings.java
new file mode 100644
index 0000000000000000000000000000000000000000..6128ea0d30a0034e29541ba7aeeefa4c3e99ecff
--- /dev/null
+++ b/blimp/client/core/settings/android/java/src/org/chromium/blimp/core/settings/Settings.java
@@ -0,0 +1,83 @@
+// Copyright 2016 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.blimp.core.settings;
+
+import org.chromium.base.annotations.CalledByNative;
+import org.chromium.base.annotations.JNINamespace;
+
+/**
+ * Settings is a Java wrapper to allow communicating with the native Settings object.
+ */
+@JNINamespace("blimp::client")
+public class Settings {
+    @CalledByNative
+    private static Settings create(long nativeSettingsAndroid) {
+        return new Settings(nativeSettingsAndroid);
+    }
+
+    private long mNativeSettingsAndroid;
+
+    // The SettingsObserverProxy is lazily created when the first observer is added. It is used
+    // instead of directly having an ObserverList in this class to ensure there is only a single
+    // JNI hop for each call to observers.
+    private SettingsObserverProxy mObserverProxy;

[David Trainor- moved to gerrit, 2016/11/03 03:05:10]

Who cleans up the observer proxy?

[Menglin, 2016/11/03 23:17:01]

it should be cleaned up in clearNativePtr() when Settings' native object is
destroyed.

+
+    private Settings(long nativeSettingsAndroid) {
+        mNativeSettingsAndroid = nativeSettingsAndroid;
+    }
+
+    @CalledByNative
+    private long getNativePtr() {

[David Trainor- moved to gerrit, 2016/11/03 03:05:10]

Put this down below near clearNativePtr

[Menglin, 2016/11/03 23:17:01]

Done.

+        assert mNativeSettingsAndroid != 0;
+        return mNativeSettingsAndroid;
+    }
+
+    public void addObserver(SettingsObserver observer) {

[David Trainor- moved to gerrit, 2016/11/03 03:05:10]

Javadocs on some of these?  Specifically on destroy where it's important to note
that the class shouldn't be used afterwards and any method calls will have no
effect.

[Menglin, 2016/11/03 23:17:01]

Done.

+        assert mNativeSettingsAndroid != 0;
+        if (mObserverProxy == null) mObserverProxy = new SettingsObserverProxy(this);
+        mObserverProxy.addObserver(observer);
+    }
+
+    public void removeObserver(SettingsObserver observer) {
+        if (mObserverProxy == null) return;
+        mObserverProxy.removeObserver(observer);
+    }
+
+    public void destroy() {

[David Trainor- moved to gerrit, 2016/11/03 03:05:10]

Do we need this method?  I feel like this is going to be destroyed by native as
it's a unique_ptr.  We might want to be careful/explicit about the lifecycle
here.

[Menglin, 2016/11/03 23:17:01]

that's a good point. ObserverProxy should be destroyed when the Settings native
object is destroyed. But the Settings java object wouldn't need be destroyed
from java because its native object is owned by blimp_client_context_impl . I
will remove the destroy method here and add destroying the observer proxy to
clearNativePtr

+        assert mNativeSettingsAndroid != 0;
+        nativeDestroy(mNativeSettingsAndroid);
+        mNativeSettingsAndroid = 0;
+    }
+
+    // Set whether or not Blimp mode is enabled.
+    public void setEnableBlimpMode(boolean enable) {
+        if (mNativeSettingsAndroid == 0) return;
+        nativeSetEnableBlimpModeWrap(mNativeSettingsAndroid, enable);
+    }
+
+    // Set whether or not the engine sends the whole webpage at once or pieces of it based on the
+    // current viewport.
+    public void setRecordWholeDocument(boolean enable) {
+        if (mNativeSettingsAndroid == 0) return;
+        nativeSetRecordWholeDocumentWrap(mNativeSettingsAndroid, enable);
+    }
+
+    // Set whether or not to show the network stats.
+    public void setShowNetworkStats(boolean enable) {
+        if (mNativeSettingsAndroid == 0) return;
+        nativeSetShowNetworkStatsWrap(mNativeSettingsAndroid, enable);
+    }
+
+    @CalledByNative
+    private void clearNativePtr() {
+        mNativeSettingsAndroid = 0;
+    }
+
+    private native void nativeDestroy(long nativeSettingsAndroid);
+    private native void nativeSetEnableBlimpModeWrap(long nativeSettingsAndroid, boolean enable);
+    private native void nativeSetRecordWholeDocumentWrap(
+            long nativeSettingsAndroid, boolean enable);
+    private native void nativeSetShowNetworkStatsWrap(long nativeSettingsAndroid, boolean enable);
+}