[ChromeDriver] Add Chrome binaries search in system PATH

Adding searching for Chrome binaries in the system PATH as well.


bug: chromedriver:2550
Change-Id: I42c3ad1618e324c964e9b420b2399ce5c8039dab
Reviewed-on: https://chromium-review.googlesource.com/1211744
Commit-Queue: Artur Khachatryan <khachatryan@chromium.org>
Reviewed-by: John Chen <johnchen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#589445}

chrome/test/chromedriver/chrome/chrome_finder.cc

@@ -12,10 +12,13 @@
 #include "base/base_paths.h"
 #include "base/bind.h"
 #include "base/callback.h"
+#include "base/environment.h"
 #include "base/files/file_path.h"
 #include "base/files/file_util.h"
 #include "base/macros.h"
 #include "base/path_service.h"
+#include "base/strings/string_split.h"
+#include "base/strings/utf_string_conversions.h"
 #include "build/build_config.h"
 
 #if defined(OS_WIN)
@@ -64,6 +67,40 @@ void GetApplicationDirs(std::vector<base::FilePath>* locations) {
 }
 #endif
 
+void GetPathsFromEnvironment(std::vector<base::FilePath>* paths) {
+  base::FilePath::StringType delimiter;
+  base::FilePath::StringType commonPath;
+  std::string path;
+  std::unique_ptr<base::Environment> env(base::Environment::Create());
+
+  if (!env->GetVar("PATH", &path)) {
+    return;
+  }
+
+#if defined(OS_WIN)
+  commonPath = base::UTF8ToWide(path);
+  delimiter = L";";
+#else
+  commonPath = path;
+  delimiter = ":";
+#endif
+
+  std::vector<base::FilePath::StringType> path_entries = base::SplitString(
+      commonPath, delimiter, base::KEEP_WHITESPACE, base::SPLIT_WANT_ALL);
+
+  for (auto& path_entry : path_entries) {
+#if defined(OS_WIN)
+    size_t size = path_entry.size();
+    if (size >= 2 && path_entry[0] == '"' && path_entry[size - 1] == '"') {
+      path_entry.erase(0, 1);
+      path_entry.erase(size - 2, 1);
+    }
+#endif
+    if (path_entry.size() > 0)
+      paths->emplace_back(path_entry);
+  }
+}
+
 }  // namespace
 
 namespace internal {
@@ -124,6 +161,7 @@ bool FindChrome(base::FilePath* browser_exe) {
 
   std::vector<base::FilePath> locations;
   GetApplicationDirs(&locations);
+  GetPathsFromEnvironment(&locations);
   return internal::FindExe(
       base::Bind(&base::PathExists),
       browser_exes,