Devtools extensions updates

[paulirish]

We're currently lacking proper documentation for

• chrome.devtools.panels.openResource()
• (300165,
  300077). chrome.devtools.panels.sources and preprocessorScript option for inspectedWindow.reload
• applyStyleSheet
• Some outstanding bugs in chrome.devtools.inspectedWindow API doc
  (291407,
  181584)

Mostly will augment the pages within https://developer.chrome.com/extensions/api_index

[paulirish]

chrome.devtools.panels.applyStyleSheet

https://github.com/paulirish/sample-devtools-theme-extension
https://code.google.com/p/chromium/issues/detail?id=318566#c32

[paulirish]

chrome.devtools.panels

• openResource method: r151672
• applyStylesheet method: CL, sample ext, crbug
• sources property: 300165

chrome.devtools.inspectedWindow

• preprocessorScript option for reload method: 300077
• fix eval method docs: 291407,
  181584

[paulirish]

CL pending here https://chromiumcodereview.appspot.com/283603003/

[paulirish]

merged!