[inspector] Issue Debugger.paused during Debugger.enable if already paused

Bug: chromium:590878
Cq-Include-Trybots: master.tryserver.blink:linux_trusty_blink_rel
Change-Id: Id94d3557980522d98c136aa444615930bee2e3ba
Reviewed-on: https://chromium-review.googlesource.com/625159
Commit-Queue: Dmitry Gozman <dgozman@chromium.org>
Reviewed-by: Aleksey Kozyatinskiy <kozyatinskiy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#47526}

src/inspector/v8-debugger-agent-impl.cc

@@ -335,6 +335,11 @@ void V8DebuggerAgentImpl::enableImpl() {
 
   m_breakpointsActive = true;
   m_debugger->setBreakpointsActive(true);
+
+  if (isPaused()) {
+    didPause(0, v8::Local<v8::Value>(), std::vector<v8::debug::BreakpointId>(),
+             false, false, false, false);
+  }
 }
 
 Response V8DebuggerAgentImpl::enable() {

test/inspector/sessions/debugger-stepping-and-breakpoints-expected.txt

 Tests how multiple sessions interact while pausing, stepping, setting breakpoints and blackboxing.
+Connecting session 1
+Pausing in 1
+Paused in 1:
+  reason: other
+  hit breakpoints: 
+  location: <anonymous>@0
+  data: null
+Connecting session 2
+Paused in 2:
+  reason: other
+  hit breakpoints: 
+  location: <anonymous>@0
+  data: null
+Resuming in 2
+Resumed in 1
+Resumed in 2
 Setting breakpoints in 1
 Setting breakpoints in 2
 Evaluating common breakpoint in 1

test/inspector/sessions/debugger-stepping-and-breakpoints.js

@@ -27,10 +27,20 @@ function bar() {
 //# sourceURL=test2.js`, 23, 25);
 
 (async function test() {
+  InspectorTest.log('Connecting session 1');
   var session1 = contextGroup.connect();
   await session1.Protocol.Debugger.enable();
+  InspectorTest.log('Pausing in 1');
+  session1.Protocol.Runtime.evaluate({expression: 'debugger;'});
+  await waitForPaused(session1, 1);
+  InspectorTest.log('Connecting session 2');
   var session2 = contextGroup.connect();
-  await session2.Protocol.Debugger.enable();
+  var enabledPromise = session2.Protocol.Debugger.enable();
+  await waitForPaused(session2, 2);
+  await enabledPromise;
+  InspectorTest.log('Resuming in 2');
+  session2.Protocol.Debugger.resume();
+  await waitForBothResumed();
 
   InspectorTest.log('Setting breakpoints in 1');
   await session1.Protocol.Debugger.setBreakpointByUrl({url: 'test.js', lineNumber: 11});