convert to emotion

Summary:
My benchmarks have shown react-emotion to be faster than the current implementation of `styled`. For this reason, I am converting all styling to [emotion](https://emotion.sh).

Benchmark results:
{F136839093}

The syntax is very similar between the two libraries. The main difference is that emotion only allows a single function for the whole style attribute, whereas the old implementation had functions for every style-attirbute.

Before:
```
{
  color: props => props.color,
  fontSize: props => props.size,
}
```

After:
```
props => ({
  color: props.color,
  fontSize: props.size,
})
```

Reviewed By: jknoxville

Differential Revision: D9479893

fbshipit-source-id: 2c39e4618f7e52ceacb67bbec8ae26114025723f

src/chrome/BugReporterDialog.js

@@ -20,7 +20,7 @@ import {
   styled,
 } from 'sonar';
 
-const Container = FlexColumn.extends({
+const Container = styled(FlexColumn)({
   padding: 10,
 });
 
@@ -29,7 +29,7 @@ const textareaStyle = {
   marginBottom: 10,
 };
 
-const DialogContainer = styled.view({
+const DialogContainer = styled('div')({
   width: 400,
   height: 300,
   position: 'absolute',
@@ -45,25 +45,25 @@ const DialogContainer = styled.view({
   boxShadow: '0 1px 10px rgba(0, 0, 0, 0.1)',
 });
 
-const TitleInput = Input.extends({
+const TitleInput = styled(Input)({
   ...textareaStyle,
   height: 30,
 });
 
-const DescriptionTextarea = Textarea.extends({
+const DescriptionTextarea = styled(Textarea)({
   ...textareaStyle,
   flexGrow: 1,
 });
 
-const SubmitButtonContainer = styled.view({
+const SubmitButtonContainer = styled('div')({
   marginLeft: 'auto',
 });
 
-const Footer = FlexRow.extends({
+const Footer = styled(FlexRow)({
   lineHeight: '24px',
 });
 
-const CloseDoneButton = Button.extends({
+const CloseDoneButton = styled(Button)({
   width: 50,
   margin: '10px auto',
 });