If the user selects text in the current tab, and types CTRL-F,...

chrome/browser/ui/find_bar/find_bar_controller.cc

Index: chrome/browser/ui/find_bar/find_bar_controller.cc
===================================================================
--- chrome/browser/ui/find_bar/find_bar_controller.cc	(revision 71618)
+++ chrome/browser/ui/find_bar/find_bar_controller.cc	(working copy)
@@ -7,7 +7,9 @@
 #include <algorithm>
 
 #include "base/i18n/rtl.h"
+#include "base/utf_string_conversions.h"
 #include "build/build_config.h"
+#include "chrome/browser/renderer_host/render_view_host.h"
 #include "chrome/browser/tab_contents/navigation_entry.h"
 #include "chrome/browser/ui/find_bar/find_bar.h"
 #include "chrome/browser/ui/find_bar/find_bar_state.h"
@@ -37,6 +39,8 @@
 
     tab_contents_->set_find_ui_active(true);
     find_bar_->Show(true);
+  } else {
+    MaybeOverrideText();
   }
   find_bar_->SetFocusAndSelection();
 }
@@ -204,11 +208,14 @@
 
 void FindBarController::MaybeSetPrepopulateText() {
 #if !defined(OS_MACOSX)
-  // Find out what we should show in the find text box. Usually, this will be
-  // the last search in this tab, but if no search has been issued in this tab
-  // we use the last search string (from any tab).
-  string16 find_string = tab_contents_->find_text();
+  // Find out what we should show in the find text box. If this tab contains any
+  // selected text, we use that text. Otherwise, we use the last search in this
+  // tab. If no search has been issued in this tab we use the last search string
+  // (from any tab).
+  string16 find_string = GetSelectedText();
   if (find_string.empty())
+    find_string = tab_contents_->find_text();
+  if (find_string.empty())
     find_string = tab_contents_->previous_find_text();
   if (find_string.empty()) {
     find_string =
@@ -227,3 +234,19 @@
   // the find pasteboard mechanism, so don't set the text here.
 #endif
 }
+
+void FindBarController::MaybeOverrideText() {
+#if !defined(OS_MACOSX)
+  string16 selected_text = GetSelectedText();
+  if (!selected_text.empty())
+    find_bar_->SetFindText(selected_text);
+#else
+  // Having a per-tab find_string is not compatible with OS X's find pasteboard,
+  // so we always have the same find text in all find bars. This is done through
+  // the find pasteboard mechanism, so don't set the text here.
+#endif
+}
+
+string16 FindBarController::GetSelectedText() {
+  return UTF8ToUTF16(tab_contents_->render_view_host()->selected_text());
+}