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/DevicesList.js

@@ -16,7 +16,7 @@ import {
   colors,
 } from 'sonar';
 
-const Heading = Text.extends({
+const Heading = styled(Text)({
   display: 'block',
   backgroundColor: colors.white,
   color: colors.light30,
@@ -26,7 +26,7 @@ const Heading = Text.extends({
   padding: '4px 8px 0',
 });
 
-const PopoverItem = FlexRow.extends({
+const PopoverItem = styled(FlexRow)({
   alignItems: 'center',
   borderBottom: `1px solid ${colors.light05}`,
   height: 50,
@@ -35,7 +35,7 @@ const PopoverItem = FlexRow.extends({
   },
 });
 
-const ItemTitle = Text.extends({
+const ItemTitle = styled(Text)({
   display: 'block',
   fontSize: 14,
   fontWeight: 400,
@@ -46,7 +46,7 @@ const ItemTitle = Text.extends({
   marginBottom: 1,
 });
 
-const ItemSubtitle = Text.extends({
+const ItemSubtitle = styled(Text)({
   display: 'block',
   fontWeight: 400,
   fontSize: 11,
@@ -57,20 +57,20 @@ const ItemSubtitle = Text.extends({
   whiteSpace: 'nowrap',
 });
 
-const ItemImage = FlexBox.extends({
+const ItemImage = styled(FlexBox)({
   alignItems: 'center',
   justifyContent: 'center',
   width: 40,
   flexShrink: 0,
 });
 
-const ItemContent = styled.view({
+const ItemContent = styled('div')({
   minWidth: 0,
   paddingRight: 5,
   flexGrow: 1,
 });
 
-const Section = styled.view({
+const Section = styled('div')({
   maxWidth: 260,
   borderBottom: `1px solid ${colors.light05}`,
   '&:last-child': {
@@ -78,7 +78,7 @@ const Section = styled.view({
   },
 });
 
-const Action = Button.extends({
+const Action = styled(Button)({
   border: `1px solid ${colors.macOSTitleBarButtonBorder}`,
   background: 'transparent',
   color: colors.macOSTitleBarIconSelected,