Create simple ThemeProvider and Default Theme

.flowconfig

@@ -1,7 +1,7 @@
 [ignore]
 
 # Ignore node_modules folder
-.node_modules
+<PROJECT_ROOT>/node_modules
 <PROJECT_ROOT>/ReactNativePaperExample
 
 [version]

src/DefaultTheme.js

@@ -0,0 +1,17 @@
+// @flow
+
+import {
+  indigo500,
+  indigo700,
+  pinkA200
+} from './styles/colors';
+
+const DefaultTheme = () => {
+    return {
+      primaryColor: indigo500,
+      primaryDarkColor: indigo700,
+      accentColor: pinkA200,
+    };
+};
+
+export default DefaultTheme;

src/ThemeProvider.js

@@ -0,0 +1,32 @@
+// @flow
+
+import {
+  Component,
+  PropTypes
+} from 'react';
+import DefaultTheme from './DefaultTheme';
+
+
+class ThemeProvider extends Component {
+
+  static propTypes = {
+    children: PropTypes.element,
+    theme: PropTypes.object,
+  };
+
+  static childContextTypes = {
+    theme: PropTypes.object,
+  };
+
+  getChildContext() {
+    return {
+      theme: this.props.theme || DefaultTheme(),
+    };
+  }
+
+  render() {
+    return this.props.children;
+  }
+}
+
+export default ThemeProvider;