Revert of [Battery] Allow usage from SecureContext or top-level brows…

…ing context only. (patchset #6 id:160001 of https://codereview.chromium.org/2880763002/ )

Reason for revert:
This CL should have gotten a API OWNER lgtm with an Intent to Ship. If the change is accepted by the API OWNERS, we should re-land this.

Original issue's description:
> [Battery] Allow usage from SecureContext or top-level browsing context only.
>
> Make the Battery Status API available only within a secure context that is
> also a top-level browsing context. This disallows the use of the API within
> framed content, as well as from any content that is not a secure context.
>
> Details: w3c/battery#10
>
> WPT updated in web-platform-tests/wpt#5871
>
> BUG=661792
>
> Review-Url: https://codereview.chromium.org/2880763002
> Cr-Commit-Position: refs/heads/master@{#476263}
> Committed: https://chromium.googlesource.com/chromium/src/+/3543d97ca7a33fb8ad48261ad252428555747896

[email protected],[email protected],[email protected]
# Not skipping CQ checks because original CL landed more than 1 days ago.
BUG=661792

Review-Url: https://codereview.chromium.org/2937553005
Cr-Commit-Position: refs/heads/master@{#479025}

third_party/WebKit/LayoutTests/battery-status/detached-no-crash-expected.txt

@@ -4,7 +4,7 @@ On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE
 
 
 PASS typeof(nav.getBattery()) == 'object' is true
-Error Code is 18
+PASS nav.getBattery() is undefined.
 PASS successfullyParsed is true
 
 TEST COMPLETE

third_party/WebKit/LayoutTests/battery-status/detached-no-crash.html

@@ -18,15 +18,8 @@
         w.close();
         w = null;
     } else if (event.data == "closed") {
-      nav.getBattery().then(battery => {
-        assert_unreachable('getBattery should reject on a closed window');
-      })
-      .catch(error => {
-        // DOMException.SECURITY_ERR = 18.
-        debug('Error Code is ' + error.code);
-        assert_equals(error.code, DOMException.SECURITY_ERR);
-      });
-      setTimeout(finishJSTest, 0);
+        shouldBeUndefined("nav.getBattery()");
+        finishJSTest();
     }
 }
 

third_party/WebKit/LayoutTests/external/wpt/battery-status/battery-iframe.https-expected.txt

@@ -0,0 +1,4 @@
+This is a testharness.js-based test.
+FAIL throw a 'SecurityError' when invoking navigator.getBattery() within iframe assert_unreached: Should have rejected: undefined Reached unreachable code
+Harness: the test ran to completion.
+

third_party/WebKit/LayoutTests/external/wpt/battery-status/battery-insecure-context-expected.txt

@@ -0,0 +1,4 @@
+This is a testharness.js-based test.
+FAIL navigator.getBattery() shall throw a 'SecurityError' in an insecure context assert_unreached: Should have rejected: undefined Reached unreachable code
+Harness: the test ran to completion.
+

third_party/WebKit/Source/modules/battery/NavigatorBattery.cpp

@@ -4,10 +4,8 @@
 
 #include "modules/battery/NavigatorBattery.h"
 
-#include "core/dom/DOMException.h"
-#include "core/dom/Document.h"
-#include "core/dom/ExceptionCode.h"
-#include "core/frame/LocalDOMWindow.h"
+#include "core/dom/ExecutionContext.h"
+#include "core/frame/LocalFrame.h"
 #include "modules/battery/BatteryManager.h"
 
 namespace blink {
@@ -21,26 +19,10 @@ ScriptPromise NavigatorBattery::getBattery(ScriptState* script_state,
 }
 
 ScriptPromise NavigatorBattery::getBattery(ScriptState* script_state) {
-  ExecutionContext* execution_context = ExecutionContext::From(script_state);
-
-  // Check secure context.
-  String error_message;
-  if (!execution_context->IsSecureContext(error_message)) {
-    return ScriptPromise::RejectWithDOMException(
-        script_state, DOMException::Create(kSecurityError, error_message));
-  }
-
-  // Check top-level browsing context.
-  if (!ToDocument(execution_context)->domWindow()->GetFrame() ||
-      !ToDocument(execution_context)->GetFrame()->IsMainFrame()) {
-    return ScriptPromise::RejectWithDOMException(
-        script_state, DOMException::Create(
-                          kSecurityError, "Not a top-level browsing context."));
+  if (!battery_manager_) {
+    battery_manager_ =
+        BatteryManager::Create(ExecutionContext::From(script_state));
   }
-
-  if (!battery_manager_)
-    battery_manager_ = BatteryManager::Create(execution_context);
-
   return battery_manager_->StartRequest(script_state);
 }