Fix recovery image text rendering.

Previously most devices would lose the character before a line wrap.
The log's text rendering was starting at offset 4 but none of the
arithmetic was taking this into account. It just happened to work
on the Nexus 9's 1536-pixel wide display (1536/18=85.3) but not on
a device such as the Nexus 5 (1080/18=60).

The only active part of this change is the change from 4 to 0 in the
gr_text call. The rest is just a few bits of trivial cleanup while I
was working out what was going on.

Change-Id: I9279ae323c77bc8b6ea87dc0fe009aaaec6bfa0e

screen_ui.cpp

@@ -246,12 +246,11 @@ void ScreenRecoveryUI::draw_screen_locked()
         // display from the bottom up, until we hit the top of the
         // screen, the bottom of the menu, or we've displayed the
         // entire text buffer.
-        int ty;
         int row = (text_top+text_rows-1) % text_rows;
         for (int ty = gr_fb_height() - char_height, count = 0;
              ty > y+2 && count < text_rows;
              ty -= char_height, ++count) {
-            gr_text(4, ty, text[row], 0);
+            gr_text(0, ty, text[row], 0);
             --row;
             if (row < 0) row = text_rows-1;
         }
@@ -480,8 +479,7 @@ void ScreenRecoveryUI::Print(const char *fmt, ...)
     // This can get called before ui_init(), so be careful.
     pthread_mutex_lock(&updateMutex);
     if (text_rows > 0 && text_cols > 0) {
-        char *ptr;
-        for (ptr = buf; *ptr != '\0'; ++ptr) {
+        for (char* ptr = buf; *ptr != '\0'; ++ptr) {
             if (*ptr == '\n' || text_col >= text_cols) {
                 text[text_row][text_col] = '\0';
                 text_col = 0;
@@ -521,10 +519,9 @@ void ScreenRecoveryUI::StartMenu(const char* const * headers, const char* const
 }
 
 int ScreenRecoveryUI::SelectMenu(int sel) {
-    int old_sel;
     pthread_mutex_lock(&updateMutex);
     if (show_menu > 0) {
-        old_sel = menu_sel;
+        int old_sel = menu_sel;
         menu_sel = sel;
 
         // Wrap at top and bottom.
@@ -539,7 +536,6 @@ int ScreenRecoveryUI::SelectMenu(int sel) {
 }
 
 void ScreenRecoveryUI::EndMenu() {
-    int i;
     pthread_mutex_lock(&updateMutex);
     if (show_menu > 0 && text_rows > 0 && text_cols > 0) {
         show_menu = 0;