[inspector] restore provisional breakpoints smarter

test/inspector/debugger/restore-provisional-breakpoint-by-line.js

Index: test/inspector/debugger/restore-provisional-breakpoint-by-line.js
diff --git a/test/inspector/debugger/restore-provisional-breakpoint-by-line.js b/test/inspector/debugger/restore-provisional-breakpoint-by-line.js
new file mode 100644
index 0000000000000000000000000000000000000000..272ba268c55ac2a0de69d0c7d8d6d2699deb4ba5
--- /dev/null
+++ b/test/inspector/debugger/restore-provisional-breakpoint-by-line.js
@@ -0,0 +1,91 @@
+// Copyright 2017 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+var source = `
+console.log(239);
+function test() {
+  return 42;
+}`;
+
+var longPrefix = new Array(512).join(';');
+var sourceWithLongLines = `
+function test() {
+  ${longPrefix}console.log(1);
+  ${longPrefix}console.log(2);
+  return 42;
+}`;
+
+var sourceWithLongLinesEdited = `
+function test() {
+  ${longPrefix}console.log(3);
+  ${longPrefix}console.log(1);
+  ${longPrefix}console.log(2);
+  return 42;
+}`;
+
+InspectorTest.setupScriptMap();
+Protocol.Debugger.enable();
+
+InspectorTest.runTestSuite([
+  function trivial(next) {
+      runTest({
+        lineNumber: 8,
+        url: 'test1.js',
+        sourceBefore: source,
+        sourceAfter: generateNewLines(9) + source,
+        lineOffset: 5,
+        columnOffset: 4 }).then(next);
+  },
+
+  function dontCheckMoreThenNLines(next) {
+      runTest({
+        lineNumber: 8,
+        url: 'test2.js',
+        sourceBefore: source,
+        sourceAfter: generateNewLines(17) + source,
+        lineOffset: 5,
+        columnOffset: 4 }).then(next);
+  },
+
+  function dontStoreLongStrings(next) {
+      runTest({
+        lineNumber: 14,
+        url: 'test3.js',
+        sourceBefore: sourceWithLongLines,
+        sourceAfter: sourceWithLongLinesEdited,
+        lineOffset: 12,
+        columnOffset: 0 }).then(next);
+  }
+]);
+
+function runTest(test) {
+  let isBefore = true;
+  Protocol.Debugger.onPaused(message => {
+    InspectorTest.logCallFrames([ message.params.callFrames[0] ]);
+    var source = isBefore ? test.sourceBefore : test.sourceAfter;
+    source += '\n//# sourceURL=' + test.url;
+    isBefore = false;
+    var lineNumber = message.params.callFrames[0].location.lineNumber - test.lineOffset;
+    var lineText = source.split('\n')[lineNumber];
+    InspectorTest.log('break at\'' + lineText.substr(Math.max(lineText.length - 32, 0)) + '\'');
+    Protocol.Debugger.resume();
+  });
+  Protocol.Debugger.onBreakpointResolved(InspectorTest.logMessage);
+
+  let breakpointId;
+  InspectorTest.addScript(test.sourceBefore + '\n//# sourceURL=' + test.url, test.lineOffset, test.columnOffset);
+  return InspectorTest.waitPendingTasks()
+    .then(() => Protocol.Debugger.setBreakpointByUrl({ lineNumber: test.lineNumber, url: test.url }))
+    .then(InspectorTest.logMessage)
+    .then(message => breakpointId = message.result.breakpointId)
+    .then(() => Protocol.Runtime.evaluate({ expression: 'test()' }))
+    .then(() => InspectorTest.addScript(test.sourceAfter + '\n//# sourceURL=' + test.url, test.lineOffset, test.columnOffset ))
+    .then(() => InspectorTest.waitPendingTasks())
+    .then(() => Protocol.Runtime.evaluate({ expression: 'test()' }))
+    .then(() => Protocol.Debugger.removeBreakpoint({ breakpointId: breakpointId }))
+}
+
+function generateNewLines(n) {
+  return new Array(n + 1).join('\n');
+}