Crash reporting plugin android (#328)

Summary:
This PR adds the barebone of a crash reporting plugin in android. Since there is no easy way to stack the PR's in git, creating a new PR, but this depends on the [iOS PR](https://github.com/facebook/flipper/pull/322)
Pull Request resolved: https://github.com/facebook/flipper/pull/328

Reviewed By: jknoxville, passy

Differential Revision: D13137447

Pulled By: priteshrnandgaonkar

fbshipit-source-id: 3b86cebbb1ea01601405dd7ba58e1caa2b506065

android/sample/src/main/java/com/facebook/flipper/sample/FlipperSampleApplication.java

@@ -1,5 +1,5 @@
 /*
- *  Copyright (c) 2004-present, Facebook, Inc.
+ *  Copyright (c) Facebook, Inc.
  *
  *  This source code is licensed under the MIT license found in the LICENSE
  *  file in the root directory of this source tree.
@@ -12,6 +12,7 @@ import android.content.Context;
 import android.support.annotation.Nullable;
 import com.facebook.flipper.android.AndroidFlipperClient;
 import com.facebook.flipper.core.FlipperClient;
+import com.facebook.flipper.plugins.crashreporter.CrashReporterPlugin;
 import com.facebook.flipper.plugins.example.ExampleFlipperPlugin;
 import com.facebook.flipper.plugins.inspector.DescriptorMapping;
 import com.facebook.flipper.plugins.inspector.InspectorFlipperPlugin;
@@ -64,6 +65,7 @@ public class FlipperSampleApplication extends Application {
                 new SharedPreferencesDescriptor("other_sample", Context.MODE_PRIVATE))));
     client.addPlugin(new LeakCanaryFlipperPlugin());
     client.addPlugin(new ExampleFlipperPlugin());
+    client.addPlugin(new CrashReporterPlugin());
     client.start();
 
     getSharedPreferences("sample", Context.MODE_PRIVATE).edit().putString("Hello", "world").apply();

android/sample/src/main/java/com/facebook/flipper/sample/RootComponentSpec.java

@@ -1,5 +1,5 @@
 /*
- *  Copyright (c) 2004-present, Facebook, Inc.
+ *  Copyright (c) Facebook, Inc.
  *
  *  This source code is licensed under the MIT license found in the LICENSE
  *  file in the root directory of this source tree.

android/src/main/java/com/facebook/flipper/plugins/crashreporter/CrashReporterPlugin.java

@@ -0,0 +1,77 @@
+/*
+ *  Copyright (c) Facebook, Inc.
+ *
+ *  This source code is licensed under the MIT license found in the LICENSE
+ *  file in the root directory of this source tree.
+ *
+ */
+package com.facebook.flipper.plugins.crashreporter;
+
+import android.app.Activity;
+import android.support.annotation.Nullable;
+import com.facebook.flipper.core.FlipperConnection;
+import com.facebook.flipper.core.FlipperObject;
+import com.facebook.flipper.core.FlipperPlugin;
+import java.io.PrintWriter;
+import java.io.StringWriter;
+
+public class CrashReporterPlugin implements FlipperPlugin {
+  public static final String ID = "CrashReporter";
+
+  @Nullable private Activity mActivity;
+
+  @Nullable private FlipperConnection mConnection;
+
+  @Nullable private Thread.UncaughtExceptionHandler prevHandler;
+
+  /*
+   * Activity to be used to display incoming messages
+   */
+  public void setActivity(Activity activity) {
+    mActivity = activity;
+  }
+
+  @Override
+  public void onConnect(FlipperConnection connection) {
+    mConnection = connection;
+    prevHandler = Thread.getDefaultUncaughtExceptionHandler();
+    Thread.setDefaultUncaughtExceptionHandler(
+        new Thread.UncaughtExceptionHandler() {
+          @Override
+          public void uncaughtException(Thread paramThread, Throwable paramThrowable) {
+            if (mConnection != null) {
+              FlipperConnection connection = mConnection;
+              StringWriter sw = new StringWriter();
+              PrintWriter pw = new PrintWriter(sw);
+              paramThrowable.printStackTrace(pw);
+              connection.send(
+                  "crash-report",
+                  new FlipperObject.Builder()
+                      .put("callstack", sw.toString())
+                      .put("cause", paramThrowable.toString())
+                      .put("reason", paramThrowable.toString())
+                      .build());
+            }
+            if (prevHandler != null) {
+              prevHandler.uncaughtException(paramThread, paramThrowable);
+            }
+          }
+        });
+  }
+
+  @Override
+  public void onDisconnect() {
+    mConnection = null;
+    Thread.setDefaultUncaughtExceptionHandler(prevHandler);
+  }
+
+  @Override
+  public boolean runInBackground() {
+    return true;
+  }
+
+  @Override
+  public String getId() {
+    return ID;
+  }
+}