Revert of [debug] do not report unnecessary coverage data. (patchset #4...

Revert of [debug] do not report unnecessary coverage data. (patchset #4 id:60001 of https://codereview.chromium.org/2764073004/ )

Reason for revert:
breaks layout tests:
https://build.chromium.org/p/client.v8.fyi/builders/V8-Blink%20Linux%2064/builds/14438

Original issue's description:
> [debug] do not report unnecessary coverage data.
>
> Only include function ranges for with non-0 counts or if the immediate outer function has non-0 count.
>
> R=caseq@chromium.org, jgruber@chromium.org
> BUG=v8:5808
>
> Review-Url: https://codereview.chromium.org/2764073004
> Cr-Commit-Position: refs/heads/master@{#44079}
> Committed: https://chromium.googlesource.com/v8/v8/+/a7577ede0b74967727895eba5e06dbe1d01fb56d

TBR=caseq@chromium.org,jgruber@chromium.org,yangguo@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=v8:5808

Review-Url: https://codereview.chromium.org/2769063004
Cr-Commit-Position: refs/heads/master@{#44080}

src/debug/debug-coverage.cc

@@ -121,7 +121,7 @@ Coverage* Coverage::Collect(Isolate* isolate,
 
     // Create and add new script data.
     Handle<Script> script_handle(script, isolate);
-    result->emplace_back(script_handle);
+    result->emplace_back(isolate, script_handle);
     std::vector<CoverageFunction>* functions = &result->back().functions;
 
     std::vector<SharedFunctionInfo*> sorted;
@@ -135,18 +135,11 @@ Coverage* Coverage::Collect(Isolate* isolate,
       std::sort(sorted.begin(), sorted.end(), CompareSharedFunctionInfo);
     }
 
-    // Stack to track nested functions, referring function by index.
-    std::vector<size_t> nesting;
-
     // Use sorted list to reconstruct function nesting.
     for (SharedFunctionInfo* info : sorted) {
       int start = StartPosition(info);
       int end = info->end_position();
       uint32_t count = counter_map.Get(info);
-      // Find the correct outer function based on start position.
-      while (!nesting.empty() && functions->at(nesting.back()).end <= start) {
-        nesting.pop_back();
-      }
       if (count != 0) {
         switch (collectionMode) {
           case v8::debug::Coverage::kPreciseCount:
@@ -159,18 +152,10 @@ Coverage* Coverage::Collect(Isolate* isolate,
             count = 1;
             break;
         }
-      } else if (nesting.empty() || functions->at(nesting.back()).count == 0) {
-        // Only include a function range if it has a non-0 count, or
-        // if it is directly nested inside a function with non-0 count.
-        continue;
       }
       Handle<String> name(info->DebugName(), isolate);
-      nesting.push_back(functions->size());
       functions->emplace_back(start, end, count, name);
     }
-
-    // Remove entries for scripts that have no coverage.
-    if (functions->empty()) result->pop_back();
   }
   return result;
 }

src/debug/debug-coverage.h

@@ -27,7 +27,7 @@ struct CoverageFunction {
 
 struct CoverageScript {
   // Initialize top-level function in case it has been garbage-collected.
-  explicit CoverageScript(Handle<Script> s) : script(s) {}
+  CoverageScript(Isolate* isolate, Handle<Script> s) : script(s) {}
   Handle<Script> script;
   // Functions are sorted by start position, from outer to inner function.
   std::vector<CoverageFunction> functions;

test/inspector/cpu-profiler/coverage.js

@@ -34,22 +34,6 @@ function h() {
 f(3);
 `;
 
-var nested =
-`
-var f = (function outer() {
-  function nested_0() {
-    return function nested_1() {
-      return function nested_2() {
-        return function nested_3() {}
-      }
-    }
-  }
-  function nested_4() {}
-  return nested_0();
-})();
-f()()();
-`;
-
 InspectorTest.log("Test collecting code coverage data with Profiler.collectCoverage.");
 
 function ClearAndGC() {
@@ -94,8 +78,8 @@ InspectorTest.runTestSuite([
       .then(() => Protocol.Profiler.startPreciseCoverage({callCount: true}))
       .then(() => Protocol.Runtime.compileScript({ expression: source, sourceURL: arguments.callee.name, persistScript: true }))
       .then((result) => Protocol.Runtime.runScript({ scriptId: result.result.scriptId }))
-      .then(InspectorTest.logMessage)
       .then(ClearAndGC)
+      .then(InspectorTest.logMessage)
       .then(Protocol.Profiler.takePreciseCoverage)
       .then(LogSorted)
       .then(Protocol.Profiler.takePreciseCoverage)
@@ -224,44 +208,4 @@ InspectorTest.runTestSuite([
       .then(ClearAndGC)
       .then(next);
   },
-  function testPreciseEmptyScriptCoverageEntries(next)
-  {
-    // Enabling the debugger holds onto script objects even though its
-    // functions can be garbage collected. We would get empty ScriptCoverage
-    // entires unless we remove them.
-    Protocol.Debugger.enable()
-      .then(Protocol.Runtime.enable)
-      .then(() => Protocol.Runtime.compileScript({ expression: source, sourceURL: arguments.callee.name, persistScript: true }))
-      .then((result) => Protocol.Runtime.runScript({ scriptId: result.result.scriptId }))
-      .then(ClearAndGC)
-      .then(Protocol.Profiler.enable)
-      .then(Protocol.Profiler.startPreciseCoverage)
-      .then(Protocol.Profiler.takePreciseCoverage)
-      .then(LogSorted)
-      .then(Protocol.Profiler.stopPreciseCoverage)
-      .then(Protocol.Profiler.disable)
-      .then(Protocol.Runtime.disable)
-      .then(Protocol.Debugger.disable)
-      .then(ClearAndGC)
-      .then(next);
-  },
-  function testPreciseCountCoveragePartial(next)
-  {
-    Protocol.Runtime.enable()
-      .then(Protocol.Profiler.enable)
-      .then(() => Protocol.Profiler.startPreciseCoverage({callCount: true}))
-      .then(() => Protocol.Runtime.compileScript({ expression: nested, sourceURL: arguments.callee.name, persistScript: true }))
-      .then((result) => Protocol.Runtime.runScript({ scriptId: result.result.scriptId }))
-      .then(InspectorTest.logMessage)
-      .then(Protocol.Profiler.takePreciseCoverage)
-      .then(LogSorted)
-      .then(() => Protocol.Runtime.evaluate({ expression: "f()" }))
-      .then(Protocol.Profiler.takePreciseCoverage)
-      .then(LogSorted)
-      .then(Protocol.Profiler.stopPreciseCoverage)
-      .then(Protocol.Profiler.disable)
-      .then(Protocol.Runtime.disable)
-      .then(ClearAndGC)
-      .then(next);
-  },
 ]);