[DevTools] Remove unnecessary emulation checkboxes and simplify UX.

Source/devtools/front_end/responsiveDesignView.css

 /*
  * Copyright 2014 The Chromium Authors. All rights reserved.
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 .responsive-design {
     overflow: hidden;
     position: relative;
 }
@@ skipping 94 matching lines @@
 
 .responsive-design-suite {
     display: flex;
     flex-direction: row;
     align-items: stretch;
     justify-content: flex-start;
     padding-top: 2px;
     padding-bottom: 2px;
 }
 
-.responsive-design-section > :not(:nth-child(1)) {
-    margin-left: 18px;
-}
-
 .responsive-design-suite-separator {
     flex: none;
     width: 1px;
     background-color: rgb(43, 43, 43);
     margin: 0 3px;
 }
 
 .responsive-design-suite > div:not(.responsive-design-suite-separator) {
     flex: auto;
     display: flex;
     flex-direction: row;
     align-items: center;
     justify-content: space-between;
     height: 22px;
     overflow: hidden;
 }
 
+.responsive-design-button {
+    height: 19px;
+    min-width: 70px;
+    background: rgb(64, 64, 64);
+    display: flex;
+    align-items: center;
+    justify-content: center !important;
+    cursor: pointer;
+}
+
+.responsive-design-button:hover,
+.responsive-design-button:active {
+    background: linear-gradient(to top, rgb(102, 102, 102), rgb(64, 64, 64));
+}
+
 /* Toolbar controls */
 
 .responsive-design-toolbar fieldset,
 .responsive-design-toolbar p {
     margin: 0;
     border: 0;
     padding: 0;
     display: inline-block;
 }
 
 .responsive-design-toolbar .field-error-message {
     display: none;
 }
 
+.responsive-design-toolbar label {
+    margin-right: 5px;
+    cursor: default !important;
+}
+
 .responsive-design-toolbar input[type='text'] {
     text-align: left;
     background-color: transparent;
     border: none;
     margin: 0;
     padding-bottom: 4px;
 }
 
 .responsive-design-toolbar input[type='text'].numeric {
     text-align: center;
 }
 
-.responsive-design-toolbar input[type='text']:not(.numeric) {
-    width: 100%;
-}
-
 .responsive-design-toolbar fieldset:disabled input,
 .responsive-design-toolbar fieldset:disabled button {
     opacity: 0.7;
 }
 
 .responsive-design-toolbar input[type='checkbox'] {
     -webkit-appearance: none;
     margin: auto 5px auto 0;
     border: 1px solid rgb(45, 45, 45);
     border-radius: 3px;
@@ skipping 16 matching lines @@
     background: rgb(220, 220, 220);
 }
 
 .responsive-design-toolbar input.error-input {
     color: red;
     text-decoration: line-through;
 }
 
 .responsive-design-toolbar select {
     height: 18px;
-    width: 220px;
     background-color: rgb(81, 81, 81);
     border: 0;
     margin-left: 10px;
     line-height: 16px;
 }
 
 body.platform-mac .responsive-design-toolbar select {
     position: relative;
     top: 1px;
 }
@@ skipping 54 matching lines @@
     opacity: 1;
 }
 
 .responsive-design-icon-swap:active {
     opacity: 0.8;
 }
 
 /* Expand button */
 
 .responsive-design-section-expand {
-    padding: 0 !important;
-}
-
-.responsive-design-expand-button {
-    height: 19px;
-    min-width: 70px;
-    background: rgb(64, 64, 64);
-    display: flex;
-    align-items: center;
-    justify-content: center;
-    margin: 3px;
-    cursor: pointer;
-}
-
-.responsive-design-expand-button:hover,
-.responsive-design-expand-button:active {
-    background: linear-gradient(to top, rgb(102, 102, 102), rgb(64, 64, 64));
+    padding: 3px !important;
 }
 
 .responsive-design-icon-expand {
     -webkit-mask-position: -48px 0;
     top: 0 !important;
     margin-right: 2px;
 }
 
 .responsive-design-toolbar.expanded .responsive-design-icon-expand {
     transform: rotate(180deg);
 }
 
 /* Device section */
 
 .responsive-design-section-device {
-    width: 340px;
+    width: 290px;
 }
 
 .responsive-design-section-device .responsive-design-section-separator {
     background: linear-gradient(to bottom, rgb(255, 186, 68), rgb(255, 119, 0));
 }
 
+.responsive-design-section-device select {
+    width: 220px;
+}
+
 .responsive-design-section-device input[type='text'],
+.responsive-design-section-device input[type='text']::-webkit-input-placeholder,
 .responsive-design-section-device select {
     color: rgb(255, 156, 0);
 }
 
 .responsive-design-section-device .expanded-only input[type='checkbox']:checked:after {
     background: rgb(255, 156, 0);
 }
 
 /* Network section */
 
 .responsive-design-section-network {
-    width: 280px;
+    width: 230px;
 }
 
 .responsive-design-section-network select {
     width: 150px;
+}
+
+.responsive-design-section-network input[type='text'] {
+    width: 190px;
+}
+
+.responsive-design-section-network input[type='text'],
+.responsive-design-section-network input[type='text']::-webkit-input-placeholder,
+.responsive-design-section-network select {
     color: rgb(65, 175, 255);
 }
 
 .responsive-design-section-network .responsive-design-section-separator {
     background: linear-gradient(to bottom, rgb(77, 170, 243), rgb(0, 130, 255));
 }
 
 /* Warning message */
 
 .responsive-design-warning {
     background-color: rgb(252, 234, 156);
     color: #222;
     position: absolute;
     left: 0;
     right: 0;
     top: 0;
     padding: 2px 4px;
     white-space: nowrap;
     display: flex;
     align-items: center;
     border-bottom: 1px solid rgb(171, 171, 171);
 }
 
 .responsive-design-warning > span {
     flex: auto;
     padding-left: 3px;
 }