Add drawer with state information

platform_tools/android/apps/viewer/src/main/java/org/skia/viewer/ViewerApplication.java

Index: platform_tools/android/apps/viewer/src/main/java/org/skia/viewer/ViewerApplication.java
diff --git a/platform_tools/android/apps/viewer/src/main/java/org/skia/viewer/ViewerApplication.java b/platform_tools/android/apps/viewer/src/main/java/org/skia/viewer/ViewerApplication.java
index 4b890bd5e1279cb2437a205d581b54aa04dffabc..0dee3e041d88b904c9623954fb794fc56e13b1c8 100644
--- a/platform_tools/android/apps/viewer/src/main/java/org/skia/viewer/ViewerApplication.java
+++ b/platform_tools/android/apps/viewer/src/main/java/org/skia/viewer/ViewerApplication.java
@@ -12,6 +12,7 @@ import android.app.Application;
 public class ViewerApplication extends Application {
     private long mNativeHandle = 0;
     private ViewerActivity mViewerActivity;
+    private String mStateJsonStr;
 
     static {
         System.loadLibrary("skia_android");
@@ -41,7 +42,12 @@ public class ViewerApplication extends Application {
     }
 
     public void setViewerActivity(ViewerActivity viewerActivity) {
-        this.mViewerActivity = viewerActivity;
+        mViewerActivity = viewerActivity;
+        // Note that viewerActivity might be null (called by onDestroy)
+        if (mStateJsonStr != null && mViewerActivity != null) {
+            // A new ViewerActivity is created, initialize its state
+            mViewerActivity.updateState(mStateJsonStr);
+        }
     }
 
     public void setTitle(String title) {
@@ -55,4 +61,18 @@ public class ViewerApplication extends Application {
             });
         }
     }
+
+    public void updateState(String stateJsonStr) {
+        // We have to store this state because ViewerActivity may be destroyed while the native app
+        // is still running. When a new ViewerActivity is created, we'll pass the state to it.
+        mStateJsonStr = stateJsonStr;
+        if (mViewerActivity != null) {
+            mViewerActivity.runOnUiThread(new Runnable() {
+                @Override
+                public void run() {
+                    mViewerActivity.updateState(mStateJsonStr);
+                }
+            });
+        }
+    }
 }